feat(security): security hardening, proxy support, and GL045 HTTP include warning

Security fixes:
- Path traversal guard in include: local: — paths with ../ that escape
  the repo root are rejected instead of reading arbitrary host files
- HTTP timeout (30 s) on all fetcher requests to prevent indefinite hangs
- Response size cap (10 MiB) via io.LimitReader to prevent memory exhaustion
- Cache directory and file permissions tightened to 0700/0600
- LSP Content-Length cap (64 MiB) to guard against DoS from a malicious client

New feature:
- --proxy flag on check, graph, and lsp subcommands; also proxy: key in
  .glint.yml; overrides system HTTP_PROXY / HTTPS_PROXY env vars when set;
  cmdGraph and cmdLSP now also load .glint.yml for proxy/token/url fallbacks

New lint rule:
- GL045 (Warning): include: remote: using plain http:// instead of https://

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -33,6 +33,11 @@ coverage.txt
 *.swo
 *~
 
+# VS Code extension build artifacts
+editors/vscode/node_modules/
+editors/vscode/out/
+editors/vscode/*.vsix
+
 # OS
 .DS_Store
 Thumbs.db

CHANGELOG.md

@@ -5,6 +5,38 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 This project uses [Semantic Versioning](https://semver.org).
 
+## [0.2.31] - 2026-06-26
+
+### Added
+
+- **Proxy support** — `--proxy <URL>` flag on `glint check`, `glint graph`, and `glint lsp`; also configurable via `proxy:` in `.glint.yml`. When set it takes precedence over `HTTP_PROXY` / `HTTPS_PROXY` env vars; when unset, system proxy settings are honoured automatically. Covers all remote include fetches and GitLab API calls.
+
+- **GL045: HTTP remote include warning** — new pipeline-level lint rule that warns when `include: remote:` uses a plain `http://` URL. CI templates fetched over unencrypted HTTP are at risk of in-transit tampering; `https://` is always preferred.
+
+### Fixed
+
+- **Path traversal in local includes** — `include: local:` paths containing `../` sequences that would escape the repository root (e.g. `../../etc/passwd`) are now rejected with a warning instead of reading arbitrary files from the host.
+
+- **HTTP timeout on remote fetches** — all HTTP calls in `internal/fetcher` now use a 30-second timeout; previously the client had no timeout and could hang indefinitely on slow or unresponsive servers.
+
+- **Unbounded response size** — remote include and GitLab API responses are now capped at 10 MiB using `io.LimitReader`; previously an arbitrarily large response could exhaust process memory.
+
+- **Cache file permissions** — the cache directory is created with mode `0700` (was `0755`) and cache files with `0600` (was `0644`), preventing other local users from reading cached GitLab tokens or pipeline content.
+
+- **LSP Content-Length DoS** — `glint lsp` now rejects incoming messages whose `Content-Length` header exceeds 64 MiB, preventing memory exhaustion from a malicious or misbehaving LSP client.
+
+## [0.2.30] - 2026-06-26
+
+### Added
+
+- **VS Code extension** (`editors/vscode/`) — TypeScript extension that starts `glint lsp` as a language server and connects to it via `vscode-languageclient`. Activates on YAML files; the `documentSelector` restricts LSP processing to `**/.gitlab-ci.yml` so other YAML files are unaffected. Inline error/warning squiggles appear on every save or edit. The `glint.executablePath` setting controls the binary path (default: `glint` on `PATH`). Build: `task ext-compile`; package as `.vsix`: `task ext-package`.
+
+## [0.2.29] - 2026-06-26
+
+### Added
+
+- **LSP server** (`glint lsp`) — new `internal/lsp` package and `glint lsp` subcommand that starts a Language Server Protocol server over stdin/stdout using Content-Length–framed JSON-RPC 2.0. Editors (VS Code, Neovim, Emacs, JetBrains, etc.) can connect with any generic LSP client configuration. Supported methods: `initialize`, `initialized`, `shutdown`, `exit`, `textDocument/didOpen`, `textDocument/didChange`, `textDocument/didSave`, `textDocument/didClose`. On every document open or change the server runs the full glint lint pipeline and publishes diagnostics via `textDocument/publishDiagnostics`; each diagnostic carries the rule ID as its `code` field and `"glint"` as `source`. Parse errors are surfaced as an Error diagnostic at the top of the document. Include resolution is best-effort (uses `GITLAB_TOKEN` / `GITLAB_URL` env vars; default cache dir `~/.cache/glint`). CLI flags: `--token`, `--gitlab-url`, `--cache-dir`, `--offline`.
+
 ## [0.2.28] - 2026-06-26
 
 ### Added

FEATURES.md

@@ -7,7 +7,7 @@ For planned work see [ROADMAP.md](ROADMAP.md).
 
 ## Lint rules
 
-Every finding carries a stable rule ID (`GL001` – `GL043`) that can be used to
+Every finding carries a stable rule ID (`GL001` – `GL045`) that can be used to
 suppress, filter, or look up the check. Run `glint explain <ID>` for a
 description, bad-YAML example, and fix.
 
@@ -19,6 +19,7 @@ description, bad-YAML example, and fix.
 | GL002 | ERR | `workflow.rules[*].when` must be `always` or `never` |
 | GL036 | ERR | `default.timeout` is not a valid GitLab CI duration string |
 | GL040 | WARN | A stage name appears more than once in `stages:` |
+| GL045 | WARN | `include: remote:` uses plain `http://` — CI templates fetched unencrypted; prefer `https://` |
 
 ### Job structure
 
@@ -243,9 +244,14 @@ url: https://gitlab.example.com
 
 # Default cache directory.
 cache_dir: ~/.cache/glint
+
+# HTTP proxy for remote includes and GitLab API calls.
+# Overrides HTTP_PROXY / HTTPS_PROXY env vars when set.
+# Leave empty to use system proxy settings.
+proxy: http://proxy.example.com:8080
 ```
 
-**Priority chain:** `--token`/`--gitlab-url` flags > `.glint.yml` > environment variables.
+**Priority chain:** `--token`/`--gitlab-url`/`--proxy` flags > `.glint.yml` > environment variables.
 
 ### Inline suppression (`# glint: ignore`)
 

README.md

@@ -6,7 +6,7 @@
 
 <p align="center">
   <a href="LICENSE"><img src="https://img.shields.io/badge/license-Apache%202.0-blue.svg" alt="License"></a>
-  <a href="CHANGELOG.md"><img src="https://img.shields.io/badge/release-v0.2.28-blue.svg" alt="Release"></a>
+  <a href="CHANGELOG.md"><img src="https://img.shields.io/badge/release-v0.2.31-blue.svg" alt="Release"></a>
 </p>
 
 > **Disclaimer:** This tool was built through iterative AI-assisted development with [Claude](https://claude.ai). It is experimental, incomplete, and not intended for production use. Coverage of GitLab CI keywords is best-effort and may lag behind GitLab's evolving spec. Use it at your own discretion — no correctness guarantees are made. Contributions and bug reports are welcome.
@@ -15,12 +15,14 @@ A local tool to validate and lint `.gitlab-ci.yml` pipelines without needing a G
 
 ## What it does
 
-- **Lints** — 43 rules covering pipeline structure, keyword constraints, `needs:`/`dependencies:` graphs, expression reachability, and deprecations (GL001–GL043); run `glint explain <ID>` for any rule
-- **Resolves includes** — local files, HTTPS URLs, GitLab project templates, and CI/CD Catalog components, with offline cache support
+- **Lints** — 45 rules covering pipeline structure, keyword constraints, `needs:`/`dependencies:` graphs, expression reachability, and deprecations (GL001–GL045); run `glint explain <ID>` for any rule
+- **Resolves includes** — local files, HTTPS URLs, GitLab project templates, and CI/CD Catalog components, with offline cache support and HTTP proxy support (`--proxy` flag or `proxy:` in `.glint.yml`)
 - **Simulates context** — `--branch`, `--tag`, `--source` flags evaluate `rules:if:` and `only`/`except` to show which jobs would be active, manual, or skipped; `--context branch=main --context branch=develop` prints a multi-column comparison table across multiple contexts in one run
 - **Multiple output formats** — `--format text` (default, ruff-style), `json`, `sarif` (GitHub Code Scanning / GitLab SAST), `junit`, `github` (PR annotations)
-- **Project config** — `.glint.yml` for rule suppression, severity overrides, token/URL defaults; `# glint: ignore RULE` for per-job inline suppression
+- **Project config** — `.glint.yml` for rule suppression, severity overrides, token/URL/proxy defaults; `# glint: ignore RULE` for per-job inline suppression
 - **Graph visualization** — `glint graph` prints a terminal job tree; `glint graph pipeline` renders a GitLab CI-style SVG/PNG; `--format mermaid` emits a Mermaid flowchart; `--format html` produces a self-contained HTML file with pan/zoom and a job-detail sidebar; context flags grey out skipped jobs
+- **LSP server** — `glint lsp` starts a Language Server Protocol server over stdin/stdout; connect with any LSP client to get inline diagnostics (rule ID as code, error/warning severity) in VS Code, Neovim, Emacs, JetBrains, etc.
+- **VS Code extension** — `editors/vscode/` wraps the LSP server; inline squiggles for every glint rule directly in the editor
 
 See [FEATURES.md](FEATURES.md) for the complete feature reference and lint rules table, and [ROADMAP.md](ROADMAP.md) for planned improvements.
 
@@ -52,6 +54,7 @@ Commands:
   check    Lint a pipeline file — exits 0 (clean) or 1 (errors found)
   graph    Visualise the pipeline as a job tree or Mermaid graph
   explain  Print description and fix for a lint rule
+  lsp      Start a Language Server Protocol server (stdin/stdout)
 ```
 
 Run `glint <command> --help` for all flags. See [USAGE.md](USAGE.md) for full
@@ -106,6 +109,27 @@ Copy [`action.yml`](action.yml) from this repository, or mirror this repo to Git
 
 The action downloads the glint Linux binary into `$RUNNER_TEMP` and runs `glint check`. Only Linux runners are supported (matches the available release binary).
 
+### VS Code extension
+
+Clone this repository and load the extension from `editors/vscode/`:
+
+```bash
+cd editors/vscode
+npm install          # install dependencies (once)
+npm run compile      # compile TypeScript → out/
+```
+
+Then in VS Code: **Run → Start Debugging** (F5) — this opens an Extension Development Host with glint diagnostics active for any `.gitlab-ci.yml` you open.
+
+Make sure `glint` is on your `PATH`, or set `glint.executablePath` in VS Code settings to the full path of the binary.
+
+To package a `.vsix` for local installation:
+
+```bash
+task ext-package     # produces glint-X.Y.Z.vsix
+code --install-extension glint-X.Y.Z.vsix
+```
+
 ## Development
 
 This project uses [Task](https://taskfile.dev) as a task runner.
@@ -120,6 +144,9 @@ task ci           # full check: vet → test → build → validate
 task fuzz         # run fuzz tests for the YAML parser (Ctrl-C to stop; FUZZ_TIME=60s to set duration)
 task changelog    # regenerate CHANGELOG.md from git history via git-cliff
 task changelog-next  # preview unreleased section (dry-run, no file written)
+task ext-install     # install VS Code extension npm dependencies
+task ext-compile     # compile the VS Code extension TypeScript source
+task ext-package     # package the VS Code extension as a .vsix
 task build-windows  # cross-compile for Windows x64 (requires a tagged commit → glint-<tag>.exe)
 task build-linux    # cross-compile for Linux x64 (requires a tagged commit → glint-<tag>-linux-amd64)
 task clean        # remove build artifacts

ROADMAP.md

@@ -8,23 +8,23 @@ This document tracks planned improvements to `glint`. Items are grouped by theme
 
 Pass `--branch`, `--tag`, `--source`, or `--var` to `glint check` or `glint graph` to evaluate `rules:if:` expressions and `only`/`except` filters against a specific pipeline event.
 
-- ~~**Single-context simulation**~~ — ✓ shipped v0.2.0; `--branch`, `--tag`, `--source`, `--var` flags on both subcommands; jobs classified as active / manual / skipped
-- ~~**`workflow:rules:variables:` propagation**~~ — ✓ shipped post-v0.2.0; variables from the matching workflow rule entry injected into the evaluation context before job `rules:if:` expressions are evaluated
-- ~~**Expression evaluator: multi-line `if:` values**~~ — ✓ shipped post-v0.2.0; newlines in block-scalar and folded YAML `if:` values treated as whitespace
-- ~~**Expression evaluator: `${VAR}` syntax**~~ — ✓ shipped post-v0.2.0; `${CI_COMMIT_BRANCH}` equivalent to `$CI_COMMIT_BRANCH` everywhere
-- ~~**Expression evaluator: regex flags**~~ — ✓ shipped post-v0.2.0; `/pattern/i`, `/pattern/m`, `/pattern/s` supported
-- ~~**Expression evaluator: variable as regex RHS**~~ — ✓ shipped post-v0.2.0; `$BRANCH =~ $PATTERN` where `$PATTERN` holds a `/regex/` string evaluates correctly
-- ~~**Expression evaluator: bare `true`/`false` and integer literals**~~ — ✓ shipped post-v0.2.0; `$FLAG == true`, `$COUNT == 4` compare as decimal strings matching GitLab CI behaviour
-- ~~**Implicit default context**~~ — ✓ shipped v0.2.11; defaults to `--branch main --source push` when no context flag is given, so `rules:if:` is always evaluated
-- ~~**`--list-vars` debug flag**~~ — ✓ shipped v0.2.11; prints sorted `KEY=VALUE` of all collected pipeline variables (root file + includes + workflow-rule union + effective context) to stderr
-- ~~**Variable expansion**~~ — ✓ shipped v0.2.13; `$VAR`/`${VAR}` references within variable values expanded after all sources are merged; transitive chains resolved; visible in `--list-vars`
-- ~~**Non-string scalar variables**~~ — ✓ shipped v0.2.13; `BUILD: true`, `RETRIES: 3` rendered and injected correctly instead of being silently dropped
-- ~~**YAML `\/` escape in double-quoted strings**~~ — ✓ shipped v0.2.13; regex patterns like `/^us\//` in double-quoted `if:` blocks no longer cause a parse error
-- ~~**Workflow rule strict evaluation**~~ — ✓ shipped v0.2.14; unparseable `if:` skips the rule instead of matching everything; prevents wrong variables being injected
-- ~~**Single `=` operator**~~ — ✓ shipped v0.2.14; bare `=` accepted as alias for `==` in `rules:if:` expressions
-- ~~**`rules:changes:` evaluation**~~ — ✓ shipped v0.2.21; `--changes PATH` and `--changes-from REF` flags; doublestar glob matching (`*` within segment, `**` across segments); permissive when no file list provided
-- ~~**Multi-context simulation**~~ — ✓ shipped v0.2.22; `--context KEY=VALUE[,...]`; repeatable; prints a comparison table of `active`/`manual`/`skipped`/`blocked` per job across all contexts
-- ~~**Context-scoped linting**~~ — ✓ shipped v0.2.23; jobs evaluated as `JobSkipped` in the supplied context are excluded from `needs:`/`dependencies:` cross-checks (GL027–GL031) to eliminate false-positive errors for conditionally-gated jobs
+- [x] **Single-context simulation** — shipped v0.2.0; `--branch`, `--tag`, `--source`, `--var` flags on both subcommands; jobs classified as active / manual / skipped
+- [x] **`workflow:rules:variables:` propagation** — shipped post-v0.2.0; variables from the matching workflow rule entry injected into the evaluation context before job `rules:if:` expressions are evaluated
+- [x] **Expression evaluator: multi-line `if:` values** — shipped post-v0.2.0; newlines in block-scalar and folded YAML `if:` values treated as whitespace
+- [x] **Expression evaluator: `${VAR}` syntax** — shipped post-v0.2.0; `${CI_COMMIT_BRANCH}` equivalent to `$CI_COMMIT_BRANCH` everywhere
+- [x] **Expression evaluator: regex flags** — shipped post-v0.2.0; `/pattern/i`, `/pattern/m`, `/pattern/s` supported
+- [x] **Expression evaluator: variable as regex RHS** — shipped post-v0.2.0; `$BRANCH =~ $PATTERN` where `$PATTERN` holds a `/regex/` string evaluates correctly
+- [x] **Expression evaluator: bare `true`/`false` and integer literals** — shipped post-v0.2.0; `$FLAG == true`, `$COUNT == 4` compare as decimal strings matching GitLab CI behaviour
+- [x] **Implicit default context** — shipped v0.2.11; defaults to `--branch main --source push` when no context flag is given, so `rules:if:` is always evaluated
+- [x] **`--list-vars` debug flag** — shipped v0.2.11; prints sorted `KEY=VALUE` of all collected pipeline variables (root file + includes + workflow-rule union + effective context) to stderr
+- [x] **Variable expansion** — shipped v0.2.13; `$VAR`/`${VAR}` references within variable values expanded after all sources are merged; transitive chains resolved; visible in `--list-vars`
+- [x] **Non-string scalar variables** — shipped v0.2.13; `BUILD: true`, `RETRIES: 3` rendered and injected correctly instead of being silently dropped
+- [x] **YAML `\/` escape in double-quoted strings** — shipped v0.2.13; regex patterns like `/^us\//` in double-quoted `if:` blocks no longer cause a parse error
+- [x] **Workflow rule strict evaluation** — shipped v0.2.14; unparseable `if:` skips the rule instead of matching everything; prevents wrong variables being injected
+- [x] **Single `=` operator** — shipped v0.2.14; bare `=` accepted as alias for `==` in `rules:if:` expressions
+- [x] **`rules:changes:` evaluation** — shipped v0.2.21; `--changes PATH` and `--changes-from REF` flags; doublestar glob matching (`*` within segment, `**` across segments); permissive when no file list provided
+- [x] **Multi-context simulation** — shipped v0.2.22; `--context KEY=VALUE[,...]`; repeatable; prints a comparison table of `active`/`manual`/`skipped`/`blocked` per job across all contexts
+- [x] **Context-scoped linting** — shipped v0.2.23; jobs evaluated as `JobSkipped` in the supplied context are excluded from `needs:`/`dependencies:` cross-checks (GL027–GL031) to eliminate false-positive errors for conditionally-gated jobs
 
 ---
 
@@ -32,36 +32,36 @@ Pass `--branch`, `--tag`, `--source`, or `--var` to `glint check` or `glint grap
 
 The current rule set covers the most common sources of broken pipelines. These are the gaps most likely to matter in practice.
 
-- ~~**Variable reference validation (GL032)**~~ — ✓ shipped v0.2.11; warns when a `rules:if:` expression references `$VAR` / `${VAR}` not declared anywhere in pipeline YAML; predefined GitLab namespaces (`CI_*`, `GITLAB_*`, …) exempt; variables from included files are also considered
-- ~~**`rules:if:` static reachability (GL033)**~~ — ✓ shipped v0.2.15; warns when every rule in a job's `rules:` block has `when: never`, making the job permanently excluded from any pipeline run; no `if:` evaluation required
-- ~~**`services:` validation (GL034)**~~ — ✓ shipped v0.2.16; map form requires `name`; `alias` must be a valid DNS label
-- ~~**`rules:changes` / `rules:exists` absolute path detection (GL035)**~~ — ✓ shipped v0.2.16; warns when a path starts with `/`; GitLab CI paths are always relative to the repo root
-- ~~**`timeout` format validation (GL036)**~~ — ✓ shipped v0.2.16; validates job-level and `default.timeout` against recognised GitLab CI duration strings
-- ~~**`id_tokens:` / `secrets:` required-key checks (GL037, GL038)**~~ — ✓ shipped v0.2.16; `id_tokens` entries must have `aud`; `secrets` entries must declare a provider
-- ~~**`pages:publish` + `artifacts.paths` consistency (GL039)**~~ — ✓ shipped v0.2.16; warns when the publish directory is missing from `artifacts.paths`
-- ~~**Duplicate stage names (GL040)**~~ — ✓ shipped v0.2.16; warns when a stage appears more than once in `stages:`
-- ~~**`cache:key:files` must be exact paths (GL041)**~~ — ✓ shipped v0.2.16; warns when entries look like glob patterns
-- ~~**Unreachable jobs**~~ — covered by GL033 (shipped v0.2.15); every-`when:never` rules block is statically dead
-- ~~**`inherit:` completeness (GL043)**~~ — ✓ shipped v0.2.20; warns when `inherit: default:` is declared but there's no `default:` block, or list form names fields not set in `default:`
+- [x] **Variable reference validation (GL032)** — shipped v0.2.11; warns when a `rules:if:` expression references `$VAR` / `${VAR}` not declared anywhere in pipeline YAML; predefined GitLab namespaces (`CI_*`, `GITLAB_*`, …) exempt; variables from included files are also considered
+- [x] **`rules:if:` static reachability (GL033)** — shipped v0.2.15; warns when every rule in a job's `rules:` block has `when: never`, making the job permanently excluded from any pipeline run; no `if:` evaluation required
+- [x] **`services:` validation (GL034)** — shipped v0.2.16; map form requires `name`; `alias` must be a valid DNS label
+- [x] **`rules:changes` / `rules:exists` absolute path detection (GL035)** — shipped v0.2.16; warns when a path starts with `/`; GitLab CI paths are always relative to the repo root
+- [x] **`timeout` format validation (GL036)** — shipped v0.2.16; validates job-level and `default.timeout` against recognised GitLab CI duration strings
+- [x] **`id_tokens:` / `secrets:` required-key checks (GL037, GL038)** — shipped v0.2.16; `id_tokens` entries must have `aud`; `secrets` entries must declare a provider
+- [x] **`pages:publish` + `artifacts.paths` consistency (GL039)** — shipped v0.2.16; warns when the publish directory is missing from `artifacts.paths`
+- [x] **Duplicate stage names (GL040)** — shipped v0.2.16; warns when a stage appears more than once in `stages:`
+- [x] **`cache:key:files` must be exact paths (GL041)** — shipped v0.2.16; warns when entries look like glob patterns
+- [x] **Unreachable jobs** — covered by GL033 (shipped v0.2.15); every-`when:never` rules block is statically dead
+- [x] **`inherit:` completeness (GL043)** — shipped v0.2.20; warns when `inherit: default:` is declared but there's no `default:` block, or list form names fields not set in `default:`
 
 ---
 
 ## Include resolution
 
-- ~~**`include: local:`** full resolution~~ — ✓ shipped in v0.2.0; local files are read from disk, recursively resolved, and merged before linting
-- ~~**`include: remote:`** (URL)~~ — ✓ shipped post-v0.2.0; plain HTTPS URLs are fetched (unauthenticated), parsed, and merged; sub-includes are resolved recursively; unreachable URLs emit `[WARNING]` and linting continues
-- ~~**Recursive include depth limit**~~ — ✓ shipped v0.2.17; depth capped at 100 (matching GitLab); project/component includes now tracked in visited set to prevent cross-file cycles
-- ~~**Offline mode / cache**~~ — ✓ shipped v0.2.17; `--cache-dir DIR` persists fetched templates; `--offline` serves from cache only; default cache dir (`~/.cache/glint`) used automatically with `--offline`
-- ~~**`include: inputs:`**~~ — ✓ shipped v0.2.17; `$[[ inputs.KEY ]]` and `$[[ inputs.KEY | default(…) ]]` placeholders in fetched component YAML are substituted from the include's `with:` block before parsing
+- [x] **`include: local:` full resolution** — shipped v0.2.0; local files are read from disk, recursively resolved, and merged before linting
+- [x] **`include: remote:` (URL)** — shipped post-v0.2.0; plain HTTPS URLs are fetched (unauthenticated), parsed, and merged; sub-includes are resolved recursively; unreachable URLs emit `[WARNING]` and linting continues
+- [x] **Recursive include depth limit** — shipped v0.2.17; depth capped at 100 (matching GitLab); project/component includes now tracked in visited set to prevent cross-file cycles
+- [x] **Offline mode / cache** — shipped v0.2.17; `--cache-dir DIR` persists fetched templates; `--offline` serves from cache only; default cache dir (`~/.cache/glint`) used automatically with `--offline`
+- [x] **`include: inputs:`** — shipped v0.2.17; `$[[ inputs.KEY ]]` and `$[[ inputs.KEY | default(…) ]]` placeholders in fetched component YAML are substituted from the include's `with:` block before parsing
 
 ---
 
-## Output formats — ✓ shipped v0.2.18
+## Output formats
 
-- ~~**JSON** (`--format json`)~~ — ✓ shipped v0.2.18; machine-readable findings with stable schema (version 1)
-- ~~**SARIF** (`--format sarif`)~~ — ✓ shipped v0.2.18; SARIF 2.1.0; consumed natively by GitHub Code Scanning and GitLab SAST
-- ~~**JUnit XML** (`--format junit`)~~ — ✓ shipped v0.2.18; lets CI pipelines publish lint results as a test report artifact
-- ~~**GitHub annotation format** (`--format github`)~~ — ✓ shipped v0.2.18; emits `::error file=…,line=…,title=RULE::message` lines so findings appear as inline comments in PR diffs
+- [x] **JSON** (`--format json`) — shipped v0.2.18; machine-readable findings with stable schema (version 1)
+- [x] **SARIF** (`--format sarif`) — shipped v0.2.18; SARIF 2.1.0; consumed natively by GitHub Code Scanning and GitLab SAST
+- [x] **JUnit XML** (`--format junit`) — shipped v0.2.18; lets CI pipelines publish lint results as a test report artifact
+- [x] **GitHub annotation format** (`--format github`) — shipped v0.2.18; emits `::error file=…,line=…,title=RULE::message` lines so findings appear as inline comments in PR diffs
 
 ---
 
@@ -69,55 +69,63 @@ The current rule set covers the most common sources of broken pipelines. These a
 
 The SVG renderer and terminal tree cover the basic layout. These would bring it closer to GitLab's full interactive view.
 
-- ~~**Terminal job tree**~~ — ✓ shipped in v0.2.0 as `glint graph tree`; stages as branches, jobs as leaves, context-aware annotations
-- ~~**`glint graph includes` shows jobs per file**~~ — ✓ shipped post-v0.2.0; each include node shows the jobs it defines as dashed-arrow rounded nodes in a distinct style
-- ~~**Multi-job connector accuracy**~~ — ✓ shipped v0.2.25; classic mode uses a bus-bar pattern (vertical rail at the midpoint + horizontal stubs per job) instead of a single center-to-center line, so uneven columns look correct
-- ~~**Job tooltip / detail panel**~~ — ✓ shipped v0.2.25; each chip is wrapped in `<g data-job="…"><title>…</title><desc>…</desc>` — SVG viewers show stage, when, image, and needs on hover; HTML output uses the data for the sidebar
-- ~~**`when: on_failure` visual distinction**~~ — ✓ shipped v0.2.25; dashed chip border + X-mark icon + red circle (`#d9534f`); legend entry added; Mermaid `on_failure` class wired
-- ~~**Blocked / skipped state colouring**~~ — ✓ shipped v0.2.25; `glint graph pipeline` accepts context flags (`--branch`, `--tag`, etc.); jobs evaluated as skipped are greyed out (`#868686`) with dimmed text and no icon
-- ~~**Interactive HTML output**~~ — ✓ shipped v0.2.25; `glint graph pipeline --format html` writes a self-contained `.html` file with mouse pan/zoom and a click-to-open job-detail sidebar; no external dependencies
-- ~~**Mermaid pipeline output**~~ — ✓ shipped v0.2.25; `glint graph pipeline --format mermaid` prints a Mermaid flowchart to stdout (paste into mermaid.live)
-- ~~**Same-stage job ordering**~~ — ✓ shipped v0.2.26; jobs within a stage that have `needs:` between each other are placed in topological sub-columns (left-to-right by depth); stage header spans all sub-columns
-- ~~**Graph links rendered behind job chips**~~ — ✓ shipped v0.2.26; SVG connectors (Bézier curves and bus-bar stubs) are drawn before job chips so lines pass behind rectangles
+- [x] **Terminal job tree** — shipped v0.2.0 as `glint graph tree`; stages as branches, jobs as leaves, context-aware annotations
+- [x] **`glint graph includes` shows jobs per file** — shipped post-v0.2.0; each include node shows the jobs it defines as dashed-arrow rounded nodes in a distinct style
+- [x] **Multi-job connector accuracy** — shipped v0.2.25; classic mode uses a bus-bar pattern (vertical rail at the midpoint + horizontal stubs per job) instead of a single center-to-center line, so uneven columns look correct
+- [x] **Job tooltip / detail panel** — shipped v0.2.25; each chip is wrapped in `<g data-job="…"><title>…</title><desc>…</desc>` — SVG viewers show stage, when, image, and needs on hover; HTML output uses the data for the sidebar
+- [x] **`when: on_failure` visual distinction** — shipped v0.2.25; dashed chip border + X-mark icon + red circle (`#d9534f`); legend entry added; Mermaid `on_failure` class wired
+- [x] **Blocked / skipped state colouring** — shipped v0.2.25; `glint graph pipeline` accepts context flags (`--branch`, `--tag`, etc.); jobs evaluated as skipped are greyed out (`#868686`) with dimmed text and no icon
+- [x] **Interactive HTML output** — shipped v0.2.25; `glint graph pipeline --format html` writes a self-contained `.html` file with mouse pan/zoom and a click-to-open job-detail sidebar; no external dependencies
+- [x] **Mermaid pipeline output** — shipped v0.2.25; `glint graph pipeline --format mermaid` prints a Mermaid flowchart to stdout (paste into mermaid.live)
+- [x] **Same-stage job ordering** — shipped v0.2.26; jobs within a stage that have `needs:` between each other are placed in topological sub-columns (left-to-right by depth); stage header spans all sub-columns
+- [x] **Graph links rendered behind job chips** — shipped v0.2.26; SVG connectors (Bézier curves and bus-bar stubs) are drawn before job chips so lines pass behind rectangles
 
 ---
 
-## Findings quality — ✓ file and line numbers shipped post-v0.2.0; ruff-style format shipped v0.2.11
+## Findings quality
 
-~~**File and line numbers on findings**~~ — ✓ shipped post-v0.2.0; every finding includes the source file and exact line of the job key. Works across local includes, remote project templates, and fetched component templates.
-
-~~**Ruff-style output format**~~ — ✓ shipped v0.2.11; findings follow `file:line: RULEID [severity] message` matching the convention used by ruff and other modern linters.
-
-**Remaining improvements**
-
-- ~~**`needs: optional: true` false-positive errors**~~ — ✓ shipped post-v0.2.0; optional missing needs are downgraded to `[WARNING]`
-- ~~**`extends:` jobs with missing script false errors**~~ — ✓ shipped post-v0.2.0; jobs using `extends:` that have no `script` after resolution emit `[WARNING]` (the script may come from an unfetchable remote base)
-- ~~**`rules:if:` static reachability (GL042)**~~ — ✓ shipped v0.2.20; warns when all `rules:if:` conditions evaluate to false given declared variable values (only fires when all referenced vars are declared in YAML)
+- [x] **File and line numbers on findings** — shipped post-v0.2.0; every finding includes the source file and exact line of the job key; works across local includes, remote project templates, and fetched component templates
+- [x] **Ruff-style output format** — shipped v0.2.11; findings follow `file:line: RULEID [severity] message` matching the convention used by ruff and other modern linters
+- [x] **`needs: optional: true` false-positive errors** — shipped post-v0.2.0; optional missing needs are downgraded to `[WARNING]`
+- [x] **`extends:` jobs with missing script false errors** — shipped post-v0.2.0; jobs using `extends:` that have no `script` after resolution emit `[WARNING]` (the script may come from an unfetchable remote base)
+- [x] **`rules:if:` static reachability (GL042)** — shipped v0.2.20; warns when all `rules:if:` conditions evaluate to false given declared variable values (only fires when all referenced vars are declared in YAML)
 
 ---
 
 ## CI / editor integration
 
-- ~~**GitLab CI template**~~ — ✓ shipped v0.2.28; `templates/check.yml` is a GitLab CI/CD Catalog component with `spec:` inputs for stage, file, version, allow_failure, and extra args; also usable as a plain local/remote include
-- ~~**GitHub Actions action**~~ — ✓ shipped v0.2.28; `action.yml` composite action downloads the glint Linux binary and runs `glint check`; mirror to GitHub as `k3nny/glint` to reference as `uses: k3nny/glint@v0.2.28`
-- ~~**Pre-commit hook**~~ — ✓ shipped v0.2.28; `.pre-commit-hooks.yaml` defines `language: golang` hook; pre-commit builds glint from source on first run and re-runs on staged `.gitlab-ci.yml` changes
-- **LSP server** — `glint lsp` mode exposing diagnostics over the Language Server Protocol; enables inline squiggles in VS Code, JetBrains, Neovim, etc. without a dedicated extension
-- **VS Code extension** — thin wrapper around the LSP server with syntax highlighting for `.gitlab-ci.yml`
+- [x] **GitLab CI template** — shipped v0.2.28; `templates/check.yml` is a GitLab CI/CD Catalog component with `spec:` inputs for stage, file, version, allow_failure, and extra args; also usable as a plain local/remote include
+- [x] **GitHub Actions action** — shipped v0.2.28; `action.yml` composite action downloads the glint Linux binary and runs `glint check`; mirror to GitHub as `k3nny/glint` to reference as `uses: k3nny/glint@v0.2.28`
+- [x] **Pre-commit hook** — shipped v0.2.28; `.pre-commit-hooks.yaml` defines `language: golang` hook; pre-commit builds glint from source on first run and re-runs on staged `.gitlab-ci.yml` changes
+- [x] **LSP server** — shipped v0.2.29; `glint lsp` runs a JSON-RPC 2.0 LSP server over stdin/stdout; `textDocument/didOpen`, `didChange`, `didSave`, `didClose` all publish diagnostics; rule IDs appear as the diagnostic `code`; include resolution is best-effort using env-var token and default cache dir
+- [x] **VS Code extension** — shipped v0.2.30; `editors/vscode/` TypeScript extension wraps `glint lsp` via `vscode-languageclient`; activates on YAML files and restricts LSP processing to `**/.gitlab-ci.yml`; configurable binary path via `glint.executablePath`; build with `task ext-compile`, package with `task ext-package`
 
 ---
 
-## Configuration — ✓ shipped v0.2.19
+## Configuration
 
-- ~~**`.glint.yml` config file**~~ — ✓ shipped v0.2.19; `ignore:`, `severity:`, `stages:`, `token:`, `url:`, `cache_dir:`; searched from the pipeline directory up to the git root
-- ~~**Inline suppression comments**~~ — ✓ shipped v0.2.19; `# glint: ignore GL007` before a job definition; comma/space-separated rules; `# glint: ignore all` wildcard
+- [x] **`.glint.yml` config file** — shipped v0.2.19; `ignore:`, `severity:`, `stages:`, `token:`, `url:`, `cache_dir:`; searched from the pipeline directory up to the git root
+- [x] **Inline suppression comments** — shipped v0.2.19; `# glint: ignore GL007` before a job definition; comma/space-separated rules; `# glint: ignore all` wildcard
+- [x] **Proxy support** — shipped v0.2.31; `--proxy` flag on `check`, `graph`, and `lsp` subcommands; also configurable via `proxy:` in `.glint.yml`; overrides `HTTP_PROXY` / `HTTPS_PROXY` env vars when set
+
+---
+
+## Security & hardening
+
+- [x] **Path traversal guard for local includes** — shipped v0.2.31; `include: local:` paths containing `../../` or similar sequences are rejected instead of reading files outside the repository root
+- [x] **HTTP timeout on remote fetches** — shipped v0.2.31; all HTTP calls via the fetcher use a 30-second timeout to prevent indefinite hangs on slow or unresponsive servers
+- [x] **Unbounded response size cap** — shipped v0.2.31; remote include and GitLab API responses are capped at 10 MiB; responses exceeding the limit are rejected to prevent memory exhaustion
+- [x] **Cache file permissions** — shipped v0.2.31; cache directories are created with mode `0700` and cache files with mode `0600`; previously used world-readable `0755`/`0644`
+- [x] **GL045: HTTP remote include warning** — shipped v0.2.31; warns when `include: remote:` uses a plain `http://` URL; CI templates fetched unencrypted are at risk of tampering
+- [x] **LSP Content-Length DoS cap** — shipped v0.2.31; `glint lsp` rejects messages with `Content-Length` exceeding 64 MiB to prevent memory exhaustion from a malicious client
 
 ---
 
 ## Reliability and developer experience
 
-- ~~**Structured rule IDs**~~ — ✓ shipped post-v0.2.0; GL001–GL031 assigned; GL032 added v0.2.11; GL033 added v0.2.15; GL034–GL041 added v0.2.16; output formats (--format json/sarif/junit/github) added v0.2.18; GL042–GL043 added v0.2.20; GL044 added v0.2.24; graph improvements shipped v0.2.25–v0.2.26
-- ~~**`glint explain <rule-id>`**~~ — ✓ shipped v0.2.20; prints rule description, rationale, bad-YAML example, and fix; `glint explain` (no arg) lists all rules
-- ~~**Semantic versioning and first release**~~ — shipped as `v0.1.0` (2026-06-07)
-- ~~**Subcommand CLI**~~ — shipped as `v0.2.0` (2026-06-11); `glint check` / `glint graph [mode]` with ruff-style `--help`
-- ~~**Changelog automation**~~ — ✓ shipped v0.2.27; `cliff.toml` configures git-cliff to produce Keep-a-Changelog–compatible release notes from Conventional Commits; `task changelog` regenerates `CHANGELOG.md`, `task changelog-next` previews unreleased entries
-- ~~**Fuzz testing**~~ — ✓ shipped v0.2.27; `FuzzParseBytes` and `FuzzSanitizeYAMLEscapes` in `internal/model/fuzz_test.go`; seeds run as regular tests in CI; `task fuzz` runs them continuously (default 30 s)
+- [x] **Structured rule IDs** — shipped post-v0.2.0; GL001–GL031 assigned; GL032 added v0.2.11; GL033 added v0.2.15; GL034–GL041 added v0.2.16; output formats added v0.2.18; GL042–GL043 added v0.2.20; GL044 added v0.2.24; graph improvements shipped v0.2.25–v0.2.26
+- [x] **`glint explain <rule-id>`** — shipped v0.2.20; prints rule description, rationale, bad-YAML example, and fix; `glint explain` (no arg) lists all rules
+- [x] **Semantic versioning and first release** — shipped v0.1.0 (2026-06-07)
+- [x] **Subcommand CLI** — shipped v0.2.0 (2026-06-11); `glint check` / `glint graph [mode]` with ruff-style `--help`
+- [x] **Changelog automation** — shipped v0.2.27; `cliff.toml` configures git-cliff to produce Keep-a-Changelog–compatible release notes from Conventional Commits; `task changelog` regenerates `CHANGELOG.md`, `task changelog-next` previews unreleased entries
+- [x] **Fuzz testing** — shipped v0.2.27; `FuzzParseBytes` and `FuzzSanitizeYAMLEscapes` in `internal/model/fuzz_test.go`; seeds run as regular tests in CI; `task fuzz` runs them continuously (default 30 s)

Taskfile.yml

@@ -123,6 +123,8 @@ tasks:
         ignore_error: false
       - cmd: ./{{.BINARY}} explain GL044
         ignore_error: false
+      - cmd: ./{{.BINARY}} check testdata/insecure_remote_include.yml
+        ignore_error: false
       - cmd: ./{{.BINARY}} explain
         ignore_error: false
 
@@ -192,6 +194,22 @@ tasks:
     desc: "Preview unreleased changelog entries without writing (requires git-cliff)"
     cmd: git cliff --config cliff.toml --unreleased
 
+  ext-install:
+    desc: Install VS Code extension npm dependencies (run once after checkout)
+    dir: editors/vscode
+    cmd: npm install
+
+  ext-compile:
+    desc: Compile the VS Code extension TypeScript source
+    dir: editors/vscode
+    cmd: npm run compile
+
+  ext-package:
+    desc: Package the VS Code extension into a .vsix file
+    dir: editors/vscode
+    deps: [ext-compile]
+    cmd: npm run package
+
   clean:
     desc: Remove build artifacts
     cmd: rm -f {{.BINARY}} {{.BINARY}}-*.exe {{.BINARY}}-*-linux-amd64

cmd/glint/lsp.go

@@ -0,0 +1,100 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+
+	"git.k3nny.fr/glint/internal/config"
+	"git.k3nny.fr/glint/internal/fetcher"
+	"git.k3nny.fr/glint/internal/lsp"
+)
+
+func cmdLSP(args []string) {
+	fs := flag.NewFlagSet("glint lsp", flag.ExitOnError)
+	token := fs.String("token", "", "GitLab personal access token (overrides GITLAB_TOKEN)")
+	gitlabURL := fs.String("gitlab-url", "", "GitLab instance URL (overrides CI_SERVER_URL / GITLAB_URL)")
+	cacheDir := fs.String("cache-dir", "", "directory for caching fetched remote includes")
+	offline := fs.Bool("offline", false, "skip all network calls; serve only from --cache-dir")
+	proxy := fs.String("proxy", "", "HTTP proxy URL for remote includes and GitLab API calls (e.g. http://proxy:8080); overrides system proxy env vars")
+	fs.Usage = func() {
+		fmt.Fprintf(os.Stderr, "glint %s\n\n", version)
+		fmt.Fprint(os.Stderr, `Start a Language Server Protocol server for .gitlab-ci.yml files.
+
+Reads JSON-RPC 2.0 messages from stdin and writes responses to stdout using
+the standard Content-Length framing. Connect with any LSP client (VS Code,
+Neovim, Emacs, etc.).
+
+Usage: glint lsp [OPTIONS]
+
+Options:
+      --token <TOKEN>
+          GitLab personal access token used for resolving project: and
+          component: includes. Defaults to GITLAB_TOKEN env var.
+
+      --gitlab-url <URL>
+          GitLab instance URL for resolving remote includes.
+          [env: CI_SERVER_URL | GITLAB_URL] [default: https://gitlab.com]
+
+      --cache-dir <DIR>
+          Cache directory for fetched remote includes. Defaults to
+          ~/.cache/glint so subsequent opens are served from cache.
+
+      --offline
+          Do not make any network calls; resolve only local includes.
+          Implies --cache-dir default (~/.cache/glint) when not set.
+
+      --proxy <URL>
+          HTTP proxy URL for remote includes and GitLab API calls
+          (e.g. http://proxy:8080). Overrides system proxy env vars
+          (HTTP_PROXY / HTTPS_PROXY). Also configurable via proxy: in
+          .glint.yml.
+
+  -h, --help
+          Print help
+
+Examples:
+  glint lsp
+  glint lsp --token glpat-xxxx --cache-dir ~/.cache/glint
+  glint lsp --offline
+  glint lsp --proxy http://proxy.example.com:8080
+`)
+	}
+	_ = fs.Parse(args)
+
+	// Load project config from the working directory (the project root from
+	// which the LSP server is launched). CLI flags take priority.
+	wd, _ := os.Getwd()
+	glintCfg, cfgErr := config.Load(wd)
+	if cfgErr != nil {
+		fmt.Fprintf(os.Stderr, "glint lsp: [warning] %s: %v\n", config.Filename, cfgErr)
+	}
+
+	fetcherToken := *token
+	if fetcherToken == "" {
+		fetcherToken = glintCfg.Token
+	}
+	fetcherURL := *gitlabURL
+	if fetcherURL == "" {
+		fetcherURL = glintCfg.URL
+	}
+	resolvedCacheDir := *cacheDir
+	if resolvedCacheDir == "" {
+		resolvedCacheDir = glintCfg.CacheDir
+	}
+	if resolvedCacheDir == "" {
+		resolvedCacheDir = defaultCacheDir()
+	}
+	resolvedProxy := *proxy
+	if resolvedProxy == "" {
+		resolvedProxy = glintCfg.Proxy
+	}
+
+	cfg := fetcher.AutoConfig().WithOverrides(fetcherURL, fetcherToken, resolvedCacheDir, *offline).WithProxy(resolvedProxy)
+
+	srv := lsp.New(os.Stdin, os.Stdout, cfg, version)
+	if err := srv.Run(); err != nil {
+		fmt.Fprintf(os.Stderr, "glint lsp: %v\n", err)
+		exit(2)
+	}
+}

cmd/glint/main.go

@@ -69,6 +69,7 @@ Commands:
   check    Lint a pipeline file — exits 0 (clean) or 1 (errors found)
   graph    Visualise the pipeline as a job tree or Mermaid graph
   explain  Show description and fix for a lint rule (e.g. glint explain GL007)
+  lsp      Start a Language Server Protocol server (stdin/stdout)
 
 Options:
   -h, --help     Print help
@@ -90,6 +91,8 @@ func main() {
 		cmdGraph(os.Args[2:])
 	case "explain":
 		cmdExplain(os.Args[2:])
+	case "lsp":
+		cmdLSP(os.Args[2:])
 	case "-h", "--help", "help":
 		fmt.Fprintf(os.Stderr, "glint %s\n\n", version)
 		fmt.Fprint(os.Stderr, globalUsage)
@@ -116,6 +119,7 @@ func cmdCheck(args []string) {
 	gitlabURL := fs.String("gitlab-url", "", "GitLab instance URL (overrides CI_SERVER_URL / GITLAB_URL)")
 	cacheDir := fs.String("cache-dir", "", "directory to cache fetched remote includes (created if needed)")
 	offline := fs.Bool("offline", false, "skip all network calls; serve only from --cache-dir")
+	proxy := fs.String("proxy", "", "HTTP proxy URL for remote includes and GitLab API calls (e.g. http://proxy:8080); overrides system proxy env vars")
 	format := fs.String("format", "text", "output format: text, json, sarif, junit, github")
 	branch := fs.String("branch", "", "simulate a branch push (sets CI_COMMIT_BRANCH, …)")
 	tag := fs.String("tag", "", "simulate a tag push (sets CI_COMMIT_TAG, …)")
@@ -283,8 +287,12 @@ Examples:
 	if *offline && resolvedCacheDir == "" {
 		resolvedCacheDir = defaultCacheDir()
 	}
+	resolvedProxy := *proxy
+	if resolvedProxy == "" {
+		resolvedProxy = glintCfg.Proxy
+	}
 
-	cfg := fetcher.AutoConfig().WithOverrides(fetcherURL, fetcherToken, resolvedCacheDir, *offline)
+	cfg := fetcher.AutoConfig().WithOverrides(fetcherURL, fetcherToken, resolvedCacheDir, *offline).WithProxy(resolvedProxy)
 
 	p, err := model.Parse(path)
 	if err != nil {
@@ -445,6 +453,7 @@ func cmdGraph(args []string) {
 	gitlabURL := fs.String("gitlab-url", "", "GitLab instance URL (overrides CI_SERVER_URL / GITLAB_URL)")
 	cacheDir := fs.String("cache-dir", "", "directory to cache fetched remote includes (created if needed)")
 	offline := fs.Bool("offline", false, "skip all network calls; serve only from --cache-dir")
+	proxy := fs.String("proxy", "", "HTTP proxy URL for remote includes and GitLab API calls (e.g. http://proxy:8080)")
 	out := fs.String("out", "glint-out", "output directory for rendered graph files (pipeline mode)")
 	format := fs.String("format", "svg", "pipeline output format: svg, mermaid, or html")
 	fs.Usage = func() {
@@ -556,13 +565,34 @@ Examples:
 		return
 	}
 	path := fs.Arg(0)
+	rootDir := filepath.Dir(filepath.Clean(path))
 
+	glintCfg, cfgErr := config.Load(rootDir)
+	if cfgErr != nil {
+		fmt.Fprintf(os.Stderr, "%s: [warning] %s: %v\n", path, config.Filename, cfgErr)
+	}
+
+	fetcherToken := *token
+	if fetcherToken == "" {
+		fetcherToken = glintCfg.Token
+	}
+	fetcherURL := *gitlabURL
+	if fetcherURL == "" {
+		fetcherURL = glintCfg.URL
+	}
 	resolvedCacheDir := *cacheDir
+	if resolvedCacheDir == "" {
+		resolvedCacheDir = glintCfg.CacheDir
+	}
 	if *offline && resolvedCacheDir == "" {
 		resolvedCacheDir = defaultCacheDir()
 	}
+	resolvedProxy := *proxy
+	if resolvedProxy == "" {
+		resolvedProxy = glintCfg.Proxy
+	}
 
-	cfg := fetcher.AutoConfig().WithOverrides(*gitlabURL, *token, resolvedCacheDir, *offline)
+	cfg := fetcher.AutoConfig().WithOverrides(fetcherURL, fetcherToken, resolvedCacheDir, *offline).WithProxy(resolvedProxy)
 
 	p, err := model.Parse(path)
 	if err != nil {
@@ -571,7 +601,6 @@ Examples:
 		return
 	}
 
-	rootDir := filepath.Dir(filepath.Clean(path))
 	resolver.ResolveIncludes(p, cfg, rootDir) //nolint:errcheck
 	resolver.Resolve(p)                       //nolint:errcheck
 

editors/vscode/.gitignore

@@ -0,0 +1,3 @@
+node_modules/
+out/
+*.vsix

editors/vscode/.vscodeignore

@@ -0,0 +1,8 @@
+src/**
+tsconfig.json
+.gitignore
+node_modules/**
+!node_modules/vscode-languageclient/**
+!node_modules/vscode-languageserver-protocol/**
+!node_modules/vscode-languageserver-types/**
+!node_modules/vscode-jsonrpc/**

editors/vscode/package.json

@@ -0,0 +1,56 @@
+{
+  "name": "glint",
+  "displayName": "glint — GitLab CI Linter",
+  "description": "Inline diagnostics for .gitlab-ci.yml pipelines powered by the glint language server",
+  "version": "0.2.29",
+  "publisher": "k3nny",
+  "license": "Apache-2.0",
+  "repository": {
+    "type": "git",
+    "url": "https://git.k3nny.fr/k3nny/glint"
+  },
+  "engines": {
+    "vscode": "^1.82.0"
+  },
+  "categories": [
+    "Linters"
+  ],
+  "keywords": [
+    "gitlab",
+    "ci",
+    "yaml",
+    "lint",
+    "pipeline"
+  ],
+  "activationEvents": [
+    "onLanguage:yaml"
+  ],
+  "main": "./out/extension.js",
+  "contributes": {
+    "configuration": {
+      "type": "object",
+      "title": "glint",
+      "properties": {
+        "glint.executablePath": {
+          "type": "string",
+          "default": "glint",
+          "markdownDescription": "Path to the `glint` binary. Leave as `glint` if it is on your `PATH`, or set an absolute path (e.g. `/usr/local/bin/glint`)."
+        }
+      }
+    }
+  },
+  "scripts": {
+    "compile": "tsc -p ./",
+    "watch": "tsc --watch -p ./",
+    "package": "vsce package"
+  },
+  "dependencies": {
+    "vscode-languageclient": "^9.0.1"
+  },
+  "devDependencies": {
+    "@types/node": "^20",
+    "@types/vscode": "^1.82.0",
+    "@vscode/vsce": "^2.22.0",
+    "typescript": "^5.3.0"
+  }
+}

editors/vscode/src/extension.ts

@@ -0,0 +1,41 @@
+import * as vscode from 'vscode';
+import {
+  LanguageClient,
+  LanguageClientOptions,
+  ServerOptions,
+  TransportKind,
+} from 'vscode-languageclient/node';
+
+let client: LanguageClient | undefined;
+
+export function activate(context: vscode.ExtensionContext): void {
+  const cfg = vscode.workspace.getConfiguration('glint');
+  const glintPath = cfg.get<string>('executablePath') || 'glint';
+
+  const serverOptions: ServerOptions = {
+    command: glintPath,
+    args: ['lsp'],
+    transport: TransportKind.stdio,
+  };
+
+  const clientOptions: LanguageClientOptions = {
+    // Only process .gitlab-ci.yml files, not all YAML.
+    documentSelector: [
+      { scheme: 'file', language: 'yaml', pattern: '**/.gitlab-ci.yml' },
+    ],
+  };
+
+  client = new LanguageClient(
+    'glint',
+    'glint — GitLab CI Linter',
+    serverOptions,
+    clientOptions,
+  );
+
+  client.start();
+  context.subscriptions.push(client);
+}
+
+export async function deactivate(): Promise<void> {
+  await client?.stop();
+}

editors/vscode/tsconfig.json

@@ -0,0 +1,15 @@
+{
+  "compilerOptions": {
+    "module": "commonjs",
+    "target": "ES2020",
+    "lib": ["ES2020"],
+    "outDir": "out",
+    "rootDir": "src",
+    "strict": true,
+    "sourceMap": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true
+  },
+  "include": ["src"],
+  "exclude": ["node_modules", "out"]
+}

go.mod

@@ -2,14 +2,15 @@ module git.k3nny.fr/glint
 
 go 1.26.4
 
+require gopkg.in/yaml.v3 v3.0.1
+
 require (
 	github.com/BurntSushi/toml v1.4.1-0.20240526193622-a339e1f7089c // indirect
 	golang.org/x/exp/typeparams v0.0.0-20231108232855-2478ac86f678 // indirect
-	golang.org/x/mod v0.31.0 // indirect
-	golang.org/x/sync v0.19.0 // indirect
-	golang.org/x/tools v0.40.1-0.20260108161641-ca281cf95054 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
-	honnef.co/go/tools v0.7.0 // indirect
+	golang.org/x/mod v0.35.0 // indirect
+	golang.org/x/sync v0.20.0 // indirect
+	golang.org/x/tools v0.44.1-0.20260420230617-19499e7caabc // indirect
+	honnef.co/go/tools v0.8.0-rc.1 // indirect
 )
 
 tool honnef.co/go/tools/cmd/staticcheck

go.sum

@@ -1,16 +1,20 @@
 github.com/BurntSushi/toml v1.4.1-0.20240526193622-a339e1f7089c h1:pxW6RcqyfI9/kWtOwnv/G+AzdKuy2ZrqINhenH4HyNs=
 github.com/BurntSushi/toml v1.4.1-0.20240526193622-a339e1f7089c/go.mod h1:ukJfTF/6rtPPRCnwkur4qwRxa8vTRFBF0uk2lLoLwho=
-golang.org/x/exp v0.0.0-20231110203233-9a3e6036ecaa h1:FRnLl4eNAQl8hwxVVC17teOw8kdjVDVAiFMtgUdTSRQ=
+github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
+github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
 golang.org/x/exp/typeparams v0.0.0-20231108232855-2478ac86f678 h1:1P7xPZEwZMoBoz0Yze5Nx2/4pxj6nw9ZqHWXqP0iRgQ=
 golang.org/x/exp/typeparams v0.0.0-20231108232855-2478ac86f678/go.mod h1:AbB0pIl9nAr9wVwH+Z2ZpaocVmF5I4GyWCDIsVjR0bk=
-golang.org/x/mod v0.31.0 h1:HaW9xtz0+kOcWKwli0ZXy79Ix+UW/vOfmWI5QVd2tgI=
-golang.org/x/mod v0.31.0/go.mod h1:43JraMp9cGx1Rx3AqioxrbrhNsLl2l/iNAvuBkrezpg=
-golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
-golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
-golang.org/x/tools v0.40.1-0.20260108161641-ca281cf95054 h1:CHVDrNHx9ZoOrNN9kKWYIbT5Rj+WF2rlwPkhbQQ5V4U=
-golang.org/x/tools v0.40.1-0.20260108161641-ca281cf95054/go.mod h1:Ik/tzLRlbscWpqqMRjyWYDisX8bG13FrdXp3o4Sr9lc=
+golang.org/x/mod v0.35.0 h1:Ww1D637e6Pg+Zb2KrWfHQUnH2dQRLBQyAtpr/haaJeM=
+golang.org/x/mod v0.35.0/go.mod h1:+GwiRhIInF8wPm+4AoT6L0FA1QWAad3OMdTRx4tFYlU=
+golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
+golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
+golang.org/x/tools v0.44.1-0.20260420230617-19499e7caabc h1:vSv/HN1q9eoPD7lMyJYVJ/GPYnqtqu6adMxUmrxOB78=
+golang.org/x/tools v0.44.1-0.20260420230617-19499e7caabc/go.mod h1:KA0AfVErSdxRZIsOVipbv3rQhVXTnlU6UhKxHd1seDI=
+golang.org/x/tools/go/expect v0.1.1-deprecated h1:jpBZDwmgPhXsKZC6WhL20P4b/wmnpsEAGHaNy0n/rJM=
+golang.org/x/tools/go/expect v0.1.1-deprecated/go.mod h1:eihoPOH+FgIqa3FpoTwguz/bVUSGBlGQU67vpBeOrBY=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-honnef.co/go/tools v0.7.0 h1:w6WUp1VbkqPEgLz4rkBzH/CSU6HkoqNLp6GstyTx3lU=
-honnef.co/go/tools v0.7.0/go.mod h1:pm29oPxeP3P82ISxZDgIYeOaf9ta6Pi0EWvCFoLG2vc=
+honnef.co/go/tools v0.8.0-rc.1 h1:wqMm2kjcEXMOr+6yau+pdKqJKe6l2N1aKPkpini+Kzk=
+honnef.co/go/tools v0.8.0-rc.1/go.mod h1:XA+OnlRA9EDh/ukGvXMNSZNKGwFQJ+5dER0ioUkOxks=

internal/config/config.go

@@ -38,6 +38,12 @@ type Config struct {
 	// CacheDir is the default directory for caching fetched remote includes.
 	// Overridden by the --cache-dir flag.
 	CacheDir string `yaml:"cache_dir"`
+
+	// Proxy is the HTTP proxy URL for fetching remote includes and GitLab API
+	// calls (e.g. "http://proxy.example.com:8080"). Overridden by the --proxy
+	// flag. When empty, system proxy settings (HTTP_PROXY / HTTPS_PROXY /
+	// NO_PROXY env vars) are used automatically.
+	Proxy string `yaml:"proxy"`
 }
 
 // Load searches for a .glint.yml file starting from dir and walking up toward

internal/fetcher/cache.go

@@ -26,10 +26,10 @@ func cacheWrite(dir, key string, data []byte) {
 	if dir == "" {
 		return
 	}
-	if err := os.MkdirAll(dir, 0o755); err != nil {
+	if err := os.MkdirAll(dir, 0o700); err != nil {
 		return
 	}
-	_ = os.WriteFile(cachePath(dir, key), data, 0o644)
+	_ = os.WriteFile(cachePath(dir, key), data, 0o600)
 }
 
 // cachePath returns the filesystem path for a cache entry.

internal/fetcher/cache_test.go

@@ -71,3 +71,28 @@ func TestCacheWrite_MkdirAll(t *testing.T) {
 		t.Errorf("directory not created: %v", err)
 	}
 }
+
+func TestCacheWrite_FilePermissions(t *testing.T) {
+	dir := t.TempDir()
+	cacheWrite(dir, "seckey", []byte("secret"))
+	info, err := os.Stat(cachePath(dir, "seckey"))
+	if err != nil {
+		t.Fatalf("stat cache file: %v", err)
+	}
+	if mode := info.Mode().Perm(); mode != 0o600 {
+		t.Errorf("cache file mode = %04o; want 0600", mode)
+	}
+}
+
+func TestCacheWrite_DirPermissions(t *testing.T) {
+	parent := t.TempDir()
+	dir := filepath.Join(parent, "glint-cache")
+	cacheWrite(dir, "k", []byte("v"))
+	info, err := os.Stat(dir)
+	if err != nil {
+		t.Fatalf("stat cache dir: %v", err)
+	}
+	if mode := info.Mode().Perm(); mode != 0o700 {
+		t.Errorf("cache dir mode = %04o; want 0700", mode)
+	}
+}

internal/fetcher/gitlab.go

@@ -8,8 +8,18 @@ import (
 	"net/url"
 	"os"
 	"strings"
+	"time"
 )
 
+// httpClient is the shared HTTP client for all fetcher requests.
+// Timeout guards against hung remote servers. Transport is intentionally nil
+// so http.DefaultTransport is used dynamically — allowing tests to swap it.
+var httpClient = &http.Client{Timeout: 30 * time.Second}
+
+// maxResponseBytes is the per-response size cap. Responses larger than this
+// are rejected to prevent memory exhaustion from pathological servers.
+const maxResponseBytes int64 = 10 << 20 // 10 MiB
+
 // TokenSource describes where a token was found, which determines the correct
 // authentication header to use with the GitLab API.
 type TokenSource int
@@ -27,6 +37,10 @@ type GitLabConfig struct {
 	Source   TokenSource
 	CacheDir string // local cache directory; empty = caching disabled
 	Offline  bool   // when true, return an error instead of making network calls
+	// ProxyURL overrides the HTTP proxy for all requests made with this config.
+	// Empty string means use system proxy settings (HTTP_PROXY / HTTPS_PROXY /
+	// NO_PROXY env vars honoured automatically by http.DefaultTransport).
+	ProxyURL string
 }
 
 // AutoConfig builds a GitLabConfig from environment variables.
@@ -56,6 +70,33 @@ func AutoConfig() GitLabConfig {
 	return cfg
 }
 
+// WithProxy returns a copy of cfg with ProxyURL set.
+func (cfg GitLabConfig) WithProxy(proxyURL string) GitLabConfig {
+	cfg.ProxyURL = proxyURL
+	return cfg
+}
+
+// client returns an HTTP client for this config.
+// When ProxyURL is set it takes precedence over system proxy env vars;
+// otherwise http.DefaultTransport's built-in ProxyFromEnvironment is used.
+func (cfg GitLabConfig) client() *http.Client {
+	if cfg.ProxyURL == "" {
+		return httpClient
+	}
+	proxyURL, err := url.Parse(cfg.ProxyURL)
+	if err != nil {
+		return httpClient
+	}
+	// Clone the default transport so all TLS/dial settings are preserved.
+	t, ok := http.DefaultTransport.(*http.Transport)
+	if !ok {
+		return httpClient
+	}
+	transport := t.Clone()
+	transport.Proxy = http.ProxyURL(proxyURL)
+	return &http.Client{Timeout: httpClient.Timeout, Transport: transport}
+}
+
 // WithOverrides returns a copy of cfg with the provided overrides applied.
 // Non-empty strings overwrite the corresponding field; booleans are always
 // applied (so offline: false explicitly clears offline mode).
@@ -128,16 +169,19 @@ func (cfg GitLabConfig) FetchFile(project, filePath, ref string) ([]byte, error)
 		}
 	}
 
-	resp, err := http.DefaultClient.Do(req)
+	resp, err := cfg.client().Do(req)
 	if err != nil {
 		return nil, fmt.Errorf("GET %s: %w", apiURL, err)
 	}
 	defer resp.Body.Close()
 
-	body, err := io.ReadAll(resp.Body)
+	body, err := io.ReadAll(io.LimitReader(resp.Body, maxResponseBytes+1))
 	if err != nil {
 		return nil, fmt.Errorf("reading response body: %w", err)
 	}
+	if int64(len(body)) > maxResponseBytes {
+		return nil, fmt.Errorf("response body exceeds maximum size (%d MiB)", maxResponseBytes>>20)
+	}
 
 	if resp.StatusCode != http.StatusOK {
 		msg := strings.TrimSpace(string(body))
@@ -169,15 +213,18 @@ func (cfg GitLabConfig) FetchURL(rawURL string) ([]byte, error) {
 		return nil, fmt.Errorf("offline mode: %s is not in the local cache (run without --offline first to populate the cache)", rawURL)
 	}
 
-	resp, err := http.Get(rawURL) //nolint:noctx
+	resp, err := cfg.client().Get(rawURL)
 	if err != nil {
 		return nil, fmt.Errorf("GET %s: %w", rawURL, err)
 	}
 	defer resp.Body.Close()
-	body, err := io.ReadAll(resp.Body)
+	body, err := io.ReadAll(io.LimitReader(resp.Body, maxResponseBytes+1))
 	if err != nil {
 		return nil, fmt.Errorf("reading body: %w", err)
 	}
+	if int64(len(body)) > maxResponseBytes {
+		return nil, fmt.Errorf("response body exceeds maximum size (%d MiB)", maxResponseBytes>>20)
+	}
 	if resp.StatusCode != http.StatusOK {
 		return nil, fmt.Errorf("GET %s: status %d", rawURL, resp.StatusCode)
 	}

internal/fetcher/gitlab_test.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"os"
+	"strings"
 	"testing"
 )
 
@@ -339,3 +340,46 @@ func TestFetchURL_NotOK(t *testing.T) {
 	_, err := cfg.FetchURL(srv.URL)
 	if err == nil { t.Fatal("expected error for non-200 status") }
 }
+
+func TestFetchFile_ResponseTooLarge(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		// Write maxResponseBytes+1 bytes to exceed the cap.
+		chunk := make([]byte, 4096)
+		written := int64(0)
+		for written <= maxResponseBytes {
+			n, _ := w.Write(chunk)
+			written += int64(n)
+		}
+	}))
+	defer srv.Close()
+	cfg := GitLabConfig{BaseURL: srv.URL}
+	_, err := cfg.FetchFile("group/project", "/ci.yml", "main")
+	if err == nil {
+		t.Fatal("expected error for oversized response")
+	}
+	if !strings.Contains(err.Error(), "exceeds maximum size") {
+		t.Errorf("unexpected error: %v", err)
+	}
+}
+
+func TestFetchURL_ResponseTooLarge(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		chunk := make([]byte, 4096)
+		written := int64(0)
+		for written <= maxResponseBytes {
+			n, _ := w.Write(chunk)
+			written += int64(n)
+		}
+	}))
+	defer srv.Close()
+	cfg := GitLabConfig{}
+	_, err := cfg.FetchURL(srv.URL)
+	if err == nil {
+		t.Fatal("expected error for oversized response")
+	}
+	if !strings.Contains(err.Error(), "exceeds maximum size") {
+		t.Errorf("unexpected error: %v", err)
+	}
+}

internal/linter/explain.go

@@ -853,4 +853,18 @@ test:
     - if: $CI_COMMIT_BRANCH == "main"
       needs: [build, lint]`,
 	},
+
+	RuleInsecureRemoteInclude: {
+		Title:    "remote include uses plain HTTP",
+		Severity: Warning,
+		Description: "An include: remote: entry uses an http:// URL instead of https://. " +
+			"CI templates fetched over plain HTTP are transmitted in cleartext; an " +
+			"attacker with network access could intercept or modify the template " +
+			"before it is parsed. Use https:// so the connection is encrypted and " +
+			"the server's identity is verified.",
+		Example: `include:
+  - remote: http://ci-templates.example.com/build.yml`,
+		Fix: `include:
+  - remote: https://ci-templates.example.com/build.yml`,
+	},
 }

internal/linter/includes.go

@@ -0,0 +1,31 @@
+package linter
+
+import (
+	"fmt"
+	"strings"
+
+	"git.k3nny.fr/glint/internal/model"
+)
+
+// checkInsecureRemoteInclude warns when an include: remote: entry uses plain
+// HTTP (GL045). The file is still fetched and linted; the finding is a warning
+// so pipelines that use HTTP for internal infra are not blocked.
+func checkInsecureRemoteInclude(p *model.Pipeline) []Finding {
+	var findings []Finding
+	for _, inc := range p.Include {
+		m, ok := inc.(map[string]any)
+		if !ok {
+			continue
+		}
+		remote, _ := m["remote"].(string)
+		if strings.HasPrefix(remote, "http://") {
+			findings = append(findings, Finding{
+				Severity: Warning,
+				Rule:     RuleInsecureRemoteInclude,
+				File:     p.SourceFile,
+				Message:  fmt.Sprintf("remote include %q uses plain HTTP; CI templates are fetched unencrypted — prefer HTTPS", remote),
+			})
+		}
+	}
+	return findings
+}

internal/linter/includes_test.go

@@ -0,0 +1,73 @@
+package linter
+
+import (
+	"testing"
+
+	"git.k3nny.fr/glint/internal/model"
+)
+
+func TestCheckInsecureRemoteInclude(t *testing.T) {
+	tests := []struct {
+		name    string
+		include []any
+		wantGL  string // expected rule ID, empty = no findings
+	}{
+		{
+			name:    "http URL triggers GL045",
+			include: []any{map[string]any{"remote": "http://example.com/ci.yml"}},
+			wantGL:  RuleInsecureRemoteInclude,
+		},
+		{
+			name:    "https URL is clean",
+			include: []any{map[string]any{"remote": "https://example.com/ci.yml"}},
+		},
+		{
+			name:    "local include ignored",
+			include: []any{map[string]any{"local": "/templates/ci.yml"}},
+		},
+		{
+			name:    "string include ignored",
+			include: []any{"/templates/ci.yml"},
+		},
+		{
+			name:    "no includes",
+			include: nil,
+		},
+		{
+			name: "mixed: http fires, https does not",
+			include: []any{
+				map[string]any{"remote": "https://ok.example.com/ci.yml"},
+				map[string]any{"remote": "http://bad.example.com/ci.yml"},
+			},
+			wantGL: RuleInsecureRemoteInclude,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			p := &model.Pipeline{
+				Include: tc.include,
+				Jobs:    map[string]model.Job{},
+			}
+			findings := checkInsecureRemoteInclude(p)
+			if tc.wantGL == "" {
+				if len(findings) != 0 {
+					t.Errorf("expected no findings, got: %v", findings)
+				}
+				return
+			}
+			found := false
+			for _, f := range findings {
+				if f.Rule == tc.wantGL {
+					found = true
+					if f.Severity != Warning {
+						t.Errorf("severity = %v; want Warning", f.Severity)
+					}
+				}
+			}
+			if !found {
+				t.Errorf("expected finding %s, got: %v", tc.wantGL, findings)
+			}
+		})
+	}
+}

internal/linter/linter.go

@@ -67,6 +67,7 @@ func Lint(p *model.Pipeline, skipped map[string]bool) []Finding {
 	findings = append(findings, checkVariableRefs(p)...)
 	findings = append(findings, checkRulesIfReachability(p)...)
 	findings = append(findings, checkInheritCompleteness(p)...)
+	findings = append(findings, checkInsecureRemoteInclude(p)...)
 	slices.SortStableFunc(findings, func(a, b Finding) int {
 		if c := cmp.Compare(a.File, b.File); c != 0 {
 			return c

internal/linter/rules.go

@@ -158,4 +158,9 @@ const (
 	// GL044: a rules:needs: entry references a job that does not exist in the pipeline.
 	// rules:needs: overrides the top-level needs: when a specific rule matches (GitLab CI 16.4+).
 	RuleRulesNeedsUnknown = "GL044"
+
+	// GL045: an include: remote: entry uses plain HTTP instead of HTTPS.
+	// CI templates fetched over HTTP are transmitted in cleartext and can be
+	// intercepted or modified in transit.
+	RuleInsecureRemoteInclude = "GL045"
 )

internal/lsp/server.go

@@ -0,0 +1,340 @@
+package lsp
+
+import (
+	"bufio"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"git.k3nny.fr/glint/internal/fetcher"
+	"git.k3nny.fr/glint/internal/linter"
+	"git.k3nny.fr/glint/internal/model"
+	"git.k3nny.fr/glint/internal/resolver"
+)
+
+// Server is a minimal Language Server Protocol server that publishes glint
+// diagnostics for .gitlab-ci.yml files opened in an editor.
+//
+// Transport: JSON-RPC 2.0 over stdin/stdout with Content-Length framing.
+// Sync mode: Full — the client sends the complete document text on every change.
+type Server struct {
+	in      *bufio.Reader
+	out     io.Writer
+	cfg     fetcher.GitLabConfig
+	version string
+	docs    map[string]string // uri → current document text
+
+	// Exit is called with the process exit code when the LSP client sends the
+	// "exit" notification. Defaults to os.Exit; replace in tests.
+	Exit func(int)
+
+	shutdownReceived bool
+}
+
+// New creates a Server reading from r and writing to w.
+func New(r io.Reader, w io.Writer, cfg fetcher.GitLabConfig, version string) *Server {
+	return &Server{
+		in:      bufio.NewReader(r),
+		out:     w,
+		cfg:     cfg,
+		version: version,
+		docs:    make(map[string]string),
+		Exit:    os.Exit,
+	}
+}
+
+// Run processes LSP messages until the connection closes or a fatal error occurs.
+// It returns nil on a clean EOF (client disconnected) and a non-nil error for
+// unrecoverable protocol failures.
+func (s *Server) Run() error {
+	for {
+		msg, err := s.readMessage()
+		if err == io.EOF {
+			return nil
+		}
+		if err != nil {
+			return fmt.Errorf("reading LSP message: %w", err)
+		}
+		if err := s.dispatch(msg); err != nil {
+			return err
+		}
+	}
+}
+
+// maxLSPMessageBytes caps the body size accepted from an LSP client.
+// A legitimate editor message is never this large; enforcing the cap prevents
+// a crafted Content-Length from triggering a multi-gigabyte allocation.
+const maxLSPMessageBytes = 64 << 20 // 64 MiB
+
+// readMessage reads one Content-Length–framed JSON-RPC message from the stream.
+func (s *Server) readMessage() (*Message, error) {
+	var contentLength int
+	for {
+		line, err := s.in.ReadString('\n')
+		if err != nil {
+			if err == io.EOF && line == "" {
+				return nil, io.EOF
+			}
+			return nil, err
+		}
+		line = strings.TrimRight(line, "\r\n")
+		if line == "" {
+			break // blank line separates headers from body
+		}
+		if strings.HasPrefix(line, "Content-Length: ") {
+			n, parseErr := strconv.Atoi(strings.TrimPrefix(line, "Content-Length: "))
+			if parseErr != nil {
+				return nil, fmt.Errorf("invalid Content-Length: %w", parseErr)
+			}
+			contentLength = n
+		}
+	}
+	if contentLength == 0 {
+		return nil, fmt.Errorf("missing or zero Content-Length header")
+	}
+	if contentLength > maxLSPMessageBytes {
+		return nil, fmt.Errorf("Content-Length %d exceeds maximum %d", contentLength, maxLSPMessageBytes)
+	}
+
+	body := make([]byte, contentLength)
+	if _, err := io.ReadFull(s.in, body); err != nil {
+		return nil, fmt.Errorf("reading message body: %w", err)
+	}
+
+	var msg Message
+	if err := json.Unmarshal(body, &msg); err != nil {
+		return nil, fmt.Errorf("unmarshalling message: %w", err)
+	}
+	return &msg, nil
+}
+
+// writeMessage encodes v as JSON and sends it with a Content-Length header.
+func (s *Server) writeMessage(v any) error {
+	body, err := json.Marshal(v)
+	if err != nil {
+		return err
+	}
+	header := fmt.Sprintf("Content-Length: %d\r\n\r\n", len(body))
+	if _, err := io.WriteString(s.out, header); err != nil {
+		return err
+	}
+	_, err = s.out.Write(body)
+	return err
+}
+
+func (s *Server) respond(id json.RawMessage, result any) error {
+	raw, err := json.Marshal(result)
+	if err != nil {
+		return err
+	}
+	return s.writeMessage(struct {
+		JSONRPC string          `json:"jsonrpc"`
+		ID      json.RawMessage `json:"id"`
+		Result  json.RawMessage `json:"result"`
+	}{"2.0", id, raw})
+}
+
+func (s *Server) respondError(id json.RawMessage, code int, message string) error {
+	return s.writeMessage(struct {
+		JSONRPC string          `json:"jsonrpc"`
+		ID      json.RawMessage `json:"id"`
+		Error   RPCError        `json:"error"`
+	}{"2.0", id, RPCError{Code: code, Message: message}})
+}
+
+func (s *Server) notify(method string, params any) error {
+	raw, err := json.Marshal(params)
+	if err != nil {
+		return err
+	}
+	return s.writeMessage(struct {
+		JSONRPC string          `json:"jsonrpc"`
+		Method  string          `json:"method"`
+		Params  json.RawMessage `json:"params"`
+	}{"2.0", method, raw})
+}
+
+// isRequest reports whether msg is a JSON-RPC request (has a non-null id).
+func isRequest(msg *Message) bool {
+	return len(msg.ID) > 0 && string(msg.ID) != "null"
+}
+
+func (s *Server) dispatch(msg *Message) error {
+	switch msg.Method {
+	case "initialize":
+		return s.handleInitialize(msg)
+	case "initialized":
+		return nil // notification; no response required
+	case "shutdown":
+		s.shutdownReceived = true
+		if isRequest(msg) {
+			return s.respond(msg.ID, nil)
+		}
+		return nil
+	case "exit":
+		code := 1
+		if s.shutdownReceived {
+			code = 0
+		}
+		s.Exit(code)
+		return nil
+	case "textDocument/didOpen":
+		return s.handleDidOpen(msg)
+	case "textDocument/didChange":
+		return s.handleDidChange(msg)
+	case "textDocument/didSave":
+		return s.handleDidSave(msg)
+	case "textDocument/didClose":
+		return s.handleDidClose(msg)
+	default:
+		if isRequest(msg) {
+			return s.respondError(msg.ID, -32601, "method not found: "+msg.Method)
+		}
+		return nil
+	}
+}
+
+func (s *Server) handleInitialize(msg *Message) error {
+	return s.respond(msg.ID, InitializeResult{
+		Capabilities: ServerCapabilities{TextDocumentSync: 1},
+		ServerInfo:   &ServerInfo{Name: "glint", Version: s.version},
+	})
+}
+
+func (s *Server) handleDidOpen(msg *Message) error {
+	var p DidOpenTextDocumentParams
+	if err := json.Unmarshal(msg.Params, &p); err != nil {
+		return nil // ignore malformed notifications
+	}
+	s.docs[p.TextDocument.URI] = p.TextDocument.Text
+	return s.lintAndPublish(p.TextDocument.URI, p.TextDocument.Text)
+}
+
+func (s *Server) handleDidChange(msg *Message) error {
+	var p DidChangeTextDocumentParams
+	if err := json.Unmarshal(msg.Params, &p); err != nil {
+		return nil
+	}
+	if len(p.ContentChanges) == 0 {
+		return nil
+	}
+	// Full sync: the last change event holds the complete new text.
+	text := p.ContentChanges[len(p.ContentChanges)-1].Text
+	s.docs[p.TextDocument.URI] = text
+	return s.lintAndPublish(p.TextDocument.URI, text)
+}
+
+func (s *Server) handleDidSave(msg *Message) error {
+	var p DidSaveTextDocumentParams
+	if err := json.Unmarshal(msg.Params, &p); err != nil {
+		return nil
+	}
+	text := s.docs[p.TextDocument.URI]
+	if p.Text != nil {
+		text = *p.Text
+		s.docs[p.TextDocument.URI] = text
+	}
+	if text == "" {
+		return nil
+	}
+	return s.lintAndPublish(p.TextDocument.URI, text)
+}
+
+func (s *Server) handleDidClose(msg *Message) error {
+	var p DidCloseTextDocumentParams
+	if err := json.Unmarshal(msg.Params, &p); err != nil {
+		return nil
+	}
+	delete(s.docs, p.TextDocument.URI)
+	// Clear diagnostics so the editor doesn't show stale squiggles.
+	return s.notify("textDocument/publishDiagnostics", PublishDiagnosticsParams{
+		URI:         p.TextDocument.URI,
+		Diagnostics: []Diagnostic{},
+	})
+}
+
+func (s *Server) lintAndPublish(uri, text string) error {
+	diags := s.lintDocument(uri, text)
+	return s.notify("textDocument/publishDiagnostics", PublishDiagnosticsParams{
+		URI:         uri,
+		Diagnostics: diags,
+	})
+}
+
+// lintDocument parses text and runs all lint rules, returning LSP Diagnostics.
+// Findings that originate from included files (not the root document) are
+// excluded; their URIs are not tracked so line numbers would be incorrect.
+func (s *Server) lintDocument(uri, text string) []Diagnostic {
+	path := uriToPath(uri)
+	if path == "" {
+		return []Diagnostic{}
+	}
+	rootDir := filepath.Dir(filepath.Clean(path))
+
+	pipeline, err := model.ParseBytes([]byte(text))
+	if err != nil {
+		return []Diagnostic{{
+			Range:    Range{Start: Position{}, End: Position{}},
+			Severity: 1,
+			Source:   "glint",
+			Message:  "YAML parse error: " + err.Error(),
+		}}
+	}
+	pipeline.SourceFile = path
+	pipeline.SetJobOrigin(path)
+
+	// Include resolution is best-effort: network failures produce warnings that
+	// are intentionally discarded here. The linter operates on whatever was
+	// successfully resolved.
+	_, _ = resolver.ResolveIncludes(pipeline, s.cfg, rootDir)
+	_, _ = resolver.Resolve(pipeline)
+
+	findings := linter.Lint(pipeline, nil)
+
+	diags := make([]Diagnostic, 0, len(findings))
+	for _, f := range findings {
+		// Skip findings from included files — their line numbers reference
+		// a different document URI that the server has not opened.
+		if f.File != path && f.File != "" {
+			continue
+		}
+		line := 0
+		if f.Line > 0 {
+			line = f.Line - 1 // glint uses 1-based lines; LSP uses 0-based
+		}
+		sev := 1 // DiagnosticSeverity: Error
+		if f.Severity == linter.Warning {
+			sev = 2 // DiagnosticSeverity: Warning
+		}
+		msg := f.Message
+		if f.Job != "" {
+			msg = fmt.Sprintf("job %q: %s", f.Job, f.Message)
+		}
+		diags = append(diags, Diagnostic{
+			Range: Range{
+				Start: Position{Line: line},
+				End:   Position{Line: line},
+			},
+			Severity: sev,
+			Code:     f.Rule,
+			Source:   "glint",
+			Message:  msg,
+		})
+	}
+	return diags
+}
+
+// uriToPath converts a file:// URI to a local filesystem path.
+// Returns an empty string for non-file URIs or on parse error.
+func uriToPath(uri string) string {
+	u, err := url.Parse(uri)
+	if err != nil || u.Scheme != "file" {
+		return ""
+	}
+	return filepath.FromSlash(u.Path)
+}

internal/lsp/server_test.go

@@ -0,0 +1,397 @@
+package lsp
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+	"testing"
+
+	"git.k3nny.fr/glint/internal/fetcher"
+)
+
+// frame encodes v as a Content-Length–framed LSP message.
+func frame(t *testing.T, v any) []byte {
+	t.Helper()
+	body, err := json.Marshal(v)
+	if err != nil {
+		t.Fatal(err)
+	}
+	hdr := fmt.Sprintf("Content-Length: %d\r\n\r\n", len(body))
+	return append([]byte(hdr), body...)
+}
+
+// readMsg reads one Content-Length–framed JSON object from r.
+func readMsg(t *testing.T, r *bufio.Reader) map[string]json.RawMessage {
+	t.Helper()
+	var contentLength int
+	for {
+		line, err := r.ReadString('\n')
+		if err != nil {
+			t.Fatalf("reading header: %v", err)
+		}
+		line = strings.TrimRight(line, "\r\n")
+		if line == "" {
+			break
+		}
+		if strings.HasPrefix(line, "Content-Length: ") {
+			n, err := strconv.Atoi(strings.TrimPrefix(line, "Content-Length: "))
+			if err != nil {
+				t.Fatalf("invalid Content-Length: %v", err)
+			}
+			contentLength = n
+		}
+	}
+	body := make([]byte, contentLength)
+	if _, err := io.ReadFull(r, body); err != nil {
+		t.Fatalf("reading body: %v", err)
+	}
+	var m map[string]json.RawMessage
+	if err := json.Unmarshal(body, &m); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	return m
+}
+
+// newTestServer returns a Server with a captured exit code and a bufio.Reader
+// wrapping the output buffer so tests can read back server messages.
+func newTestServer(input []byte) (*Server, *bytes.Buffer, *int) {
+	var out bytes.Buffer
+	exitCode := -1
+	srv := New(bytes.NewReader(input), &out, fetcher.GitLabConfig{}, "test")
+	srv.Exit = func(code int) { exitCode = code }
+	return srv, &out, &exitCode
+}
+
+func TestServer_Initialize(t *testing.T) {
+	input := frame(t, map[string]any{
+		"jsonrpc": "2.0",
+		"id":      1,
+		"method":  "initialize",
+		"params":  map[string]any{},
+	})
+	srv, out, _ := newTestServer(input)
+	srv.Run() //nolint:errcheck
+
+	resp := readMsg(t, bufio.NewReader(out))
+	if string(resp["id"]) != "1" {
+		t.Errorf("response id = %s; want 1", resp["id"])
+	}
+
+	var result InitializeResult
+	if err := json.Unmarshal(resp["result"], &result); err != nil {
+		t.Fatalf("unmarshal result: %v", err)
+	}
+	if result.Capabilities.TextDocumentSync != 1 {
+		t.Errorf("textDocumentSync = %d; want 1", result.Capabilities.TextDocumentSync)
+	}
+	if result.ServerInfo == nil || result.ServerInfo.Name != "glint" {
+		t.Errorf("serverInfo.name = %v; want glint", result.ServerInfo)
+	}
+}
+
+func TestServer_ShutdownExit(t *testing.T) {
+	var buf bytes.Buffer
+	buf.Write(frame(t, map[string]any{
+		"jsonrpc": "2.0", "id": 1, "method": "initialize", "params": map[string]any{},
+	}))
+	buf.Write(frame(t, map[string]any{
+		"jsonrpc": "2.0", "method": "initialized", "params": map[string]any{},
+	}))
+	buf.Write(frame(t, map[string]any{
+		"jsonrpc": "2.0", "id": 2, "method": "shutdown",
+	}))
+	buf.Write(frame(t, map[string]any{
+		"jsonrpc": "2.0", "method": "exit",
+	}))
+
+	srv, out, exitCode := newTestServer(buf.Bytes())
+	srv.Run() //nolint:errcheck
+
+	r := bufio.NewReader(out)
+	initResp := readMsg(t, r)
+	if string(initResp["id"]) != "1" {
+		t.Errorf("init response id = %s; want 1", initResp["id"])
+	}
+	shutResp := readMsg(t, r)
+	if string(shutResp["id"]) != "2" {
+		t.Errorf("shutdown response id = %s; want 2", shutResp["id"])
+	}
+	if string(shutResp["result"]) != "null" {
+		t.Errorf("shutdown result = %s; want null", shutResp["result"])
+	}
+	if *exitCode != 0 {
+		t.Errorf("exit code = %d; want 0", *exitCode)
+	}
+}
+
+func TestServer_ExitWithoutShutdown(t *testing.T) {
+	input := frame(t, map[string]any{
+		"jsonrpc": "2.0", "method": "exit",
+	})
+	srv, _, exitCode := newTestServer(input)
+	srv.Run() //nolint:errcheck
+
+	if *exitCode != 1 {
+		t.Errorf("exit code = %d; want 1 (no prior shutdown)", *exitCode)
+	}
+}
+
+func TestServer_MethodNotFound(t *testing.T) {
+	input := frame(t, map[string]any{
+		"jsonrpc": "2.0", "id": 99, "method": "workspace/unknownMethod",
+	})
+	srv, out, _ := newTestServer(input)
+	srv.Run() //nolint:errcheck
+
+	resp := readMsg(t, bufio.NewReader(out))
+	if resp["error"] == nil {
+		t.Errorf("expected error response for unknown method, got: %v", resp)
+	}
+	var rpcErr RPCError
+	if err := json.Unmarshal(resp["error"], &rpcErr); err != nil {
+		t.Fatalf("unmarshal error: %v", err)
+	}
+	if rpcErr.Code != -32601 {
+		t.Errorf("error code = %d; want -32601", rpcErr.Code)
+	}
+}
+
+func TestServer_UnknownNotificationIgnored(t *testing.T) {
+	// Notifications (no id) for unknown methods must be silently ignored.
+	input := frame(t, map[string]any{
+		"jsonrpc": "2.0", "method": "$/setTrace", "params": map[string]any{"value": "off"},
+	})
+	srv, out, _ := newTestServer(input)
+	srv.Run() //nolint:errcheck
+
+	if out.Len() > 0 {
+		t.Errorf("server wrote %d bytes for unknown notification; want 0", out.Len())
+	}
+}
+
+func TestServer_DidOpen_CleanPipeline(t *testing.T) {
+	yaml := `stages: [build]
+
+build-job:
+  stage: build
+  script: echo hello
+`
+	// Use a pseudo file:// URI that maps to the tmp path; include resolution
+	// will fail silently (no network, no local includes) which is fine.
+	uri := "file:///tmp/test.gitlab-ci.yml"
+
+	input := frame(t, map[string]any{
+		"jsonrpc": "2.0",
+		"method":  "textDocument/didOpen",
+		"params": map[string]any{
+			"textDocument": map[string]any{
+				"uri": uri, "languageId": "yaml", "version": 1, "text": yaml,
+			},
+		},
+	})
+	srv, out, _ := newTestServer(input)
+	srv.Run() //nolint:errcheck
+
+	notif := readMsg(t, bufio.NewReader(out))
+	if string(notif["method"]) != `"textDocument/publishDiagnostics"` {
+		t.Fatalf("method = %s; want textDocument/publishDiagnostics", notif["method"])
+	}
+	var params PublishDiagnosticsParams
+	if err := json.Unmarshal(notif["params"], &params); err != nil {
+		t.Fatalf("unmarshal params: %v", err)
+	}
+	if params.URI != uri {
+		t.Errorf("uri = %q; want %q", params.URI, uri)
+	}
+	// A clean pipeline should produce no diagnostics (or only warnings from
+	// include resolution being skipped — but those are filtered since they
+	// originate from a different file path).
+	for _, d := range params.Diagnostics {
+		if d.Severity == 1 {
+			t.Errorf("unexpected error diagnostic: %s", d.Message)
+		}
+	}
+}
+
+func TestServer_DidOpen_WithErrors(t *testing.T) {
+	// A pipeline with a job in an undeclared stage triggers GL004.
+	yaml := `stages: [build]
+
+bad-job:
+  stage: missing-stage
+  script: echo hi
+`
+	uri := "file:///tmp/bad.gitlab-ci.yml"
+	input := frame(t, map[string]any{
+		"jsonrpc": "2.0",
+		"method":  "textDocument/didOpen",
+		"params": map[string]any{
+			"textDocument": map[string]any{
+				"uri": uri, "languageId": "yaml", "version": 1, "text": yaml,
+			},
+		},
+	})
+	srv, out, _ := newTestServer(input)
+	srv.Run() //nolint:errcheck
+
+	notif := readMsg(t, bufio.NewReader(out))
+	var params PublishDiagnosticsParams
+	if err := json.Unmarshal(notif["params"], &params); err != nil {
+		t.Fatalf("unmarshal params: %v", err)
+	}
+	if len(params.Diagnostics) == 0 {
+		t.Error("expected diagnostics for pipeline with unknown stage, got none")
+	}
+	found := false
+	for _, d := range params.Diagnostics {
+		if d.Code == "GL004" {
+			found = true
+			if d.Severity != 1 {
+				t.Errorf("GL004 severity = %d; want 1 (Error)", d.Severity)
+			}
+		}
+	}
+	if !found {
+		t.Errorf("expected GL004 diagnostic, got: %v", params.Diagnostics)
+	}
+}
+
+func TestServer_DidOpen_ParseError(t *testing.T) {
+	uri := "file:///tmp/broken.gitlab-ci.yml"
+	input := frame(t, map[string]any{
+		"jsonrpc": "2.0",
+		"method":  "textDocument/didOpen",
+		"params": map[string]any{
+			"textDocument": map[string]any{
+				"uri": uri, "languageId": "yaml", "version": 1,
+				"text": "?", // bare ? yields empty job name → parse error
+			},
+		},
+	})
+	srv, out, _ := newTestServer(input)
+	srv.Run() //nolint:errcheck
+
+	notif := readMsg(t, bufio.NewReader(out))
+	var params PublishDiagnosticsParams
+	if err := json.Unmarshal(notif["params"], &params); err != nil {
+		t.Fatalf("unmarshal params: %v", err)
+	}
+	if len(params.Diagnostics) == 0 {
+		t.Fatal("expected parse-error diagnostic, got none")
+	}
+	d := params.Diagnostics[0]
+	if d.Severity != 1 {
+		t.Errorf("severity = %d; want 1 (Error)", d.Severity)
+	}
+	if !strings.Contains(d.Message, "YAML parse error") {
+		t.Errorf("message = %q; want YAML parse error", d.Message)
+	}
+}
+
+func TestServer_DidChange(t *testing.T) {
+	uri := "file:///tmp/ci.gitlab-ci.yml"
+	var buf bytes.Buffer
+	// Open with clean content.
+	buf.Write(frame(t, map[string]any{
+		"jsonrpc": "2.0", "method": "textDocument/didOpen",
+		"params": map[string]any{"textDocument": map[string]any{
+			"uri": uri, "languageId": "yaml", "version": 1,
+			"text": "stages: [build]\nbuild: {stage: build, script: echo}\n",
+		}},
+	}))
+	// Change to content with an error.
+	buf.Write(frame(t, map[string]any{
+		"jsonrpc": "2.0", "method": "textDocument/didChange",
+		"params": map[string]any{
+			"textDocument": map[string]any{"uri": uri, "version": 2},
+			"contentChanges": []map[string]any{
+				{"text": "stages: [build]\nbad: {stage: gone, script: hi}\n"},
+			},
+		},
+	}))
+
+	srv, out, _ := newTestServer(buf.Bytes())
+	srv.Run() //nolint:errcheck
+
+	r := bufio.NewReader(out)
+	_ = readMsg(t, r) // first publishDiagnostics (clean)
+	second := readMsg(t, r)
+
+	var params PublishDiagnosticsParams
+	if err := json.Unmarshal(second["params"], &params); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	if len(params.Diagnostics) == 0 {
+		t.Error("expected diagnostics after change to broken content, got none")
+	}
+}
+
+func TestServer_DidClose_ClearsdiAgnostics(t *testing.T) {
+	uri := "file:///tmp/toclose.gitlab-ci.yml"
+	var buf bytes.Buffer
+	buf.Write(frame(t, map[string]any{
+		"jsonrpc": "2.0", "method": "textDocument/didOpen",
+		"params": map[string]any{"textDocument": map[string]any{
+			"uri": uri, "languageId": "yaml", "version": 1,
+			"text": "stages: [build]\nj: {stage: build, script: echo}\n",
+		}},
+	}))
+	buf.Write(frame(t, map[string]any{
+		"jsonrpc": "2.0", "method": "textDocument/didClose",
+		"params": map[string]any{"textDocument": map[string]any{"uri": uri}},
+	}))
+
+	srv, out, _ := newTestServer(buf.Bytes())
+	srv.Run() //nolint:errcheck
+
+	r := bufio.NewReader(out)
+	_ = readMsg(t, r) // publishDiagnostics from didOpen
+
+	closeNotif := readMsg(t, r)
+	var params PublishDiagnosticsParams
+	if err := json.Unmarshal(closeNotif["params"], &params); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	if params.URI != uri {
+		t.Errorf("uri = %q; want %q", params.URI, uri)
+	}
+	if len(params.Diagnostics) != 0 {
+		t.Errorf("expected empty diagnostics on close, got %v", params.Diagnostics)
+	}
+}
+
+func TestServer_ContentLengthTooLarge(t *testing.T) {
+	// Craft a header with a content-length that exceeds the cap.
+	// The server must reject it before allocating a giant buffer.
+	header := fmt.Sprintf("Content-Length: %d\r\n\r\n", maxLSPMessageBytes+1)
+	srv, _, _ := newTestServer([]byte(header))
+	err := srv.Run()
+	if err == nil {
+		t.Fatal("expected error for oversized Content-Length, got nil")
+	}
+	if !strings.Contains(err.Error(), "exceeds maximum") {
+		t.Errorf("unexpected error: %v", err)
+	}
+}
+
+func TestServer_UriToPath(t *testing.T) {
+	tests := []struct {
+		uri  string
+		want string
+	}{
+		{"file:///tmp/ci.yml", "/tmp/ci.yml"},
+		{"file:///home/user/project/.gitlab-ci.yml", "/home/user/project/.gitlab-ci.yml"},
+		{"https://example.com/file.yml", ""},
+		{"not-a-uri", ""},
+	}
+	for _, tc := range tests {
+		got := uriToPath(tc.uri)
+		if got != tc.want {
+			t.Errorf("uriToPath(%q) = %q; want %q", tc.uri, got, tc.want)
+		}
+	}
+}

internal/lsp/types.go

@@ -0,0 +1,112 @@
+// Package lsp implements a minimal Language Server Protocol server for glint.
+package lsp
+
+import "encoding/json"
+
+// Message is a JSON-RPC 2.0 message (request, response, or notification).
+type Message struct {
+	JSONRPC string          `json:"jsonrpc"`
+	ID      json.RawMessage `json:"id,omitempty"`
+	Method  string          `json:"method,omitempty"`
+	Params  json.RawMessage `json:"params,omitempty"`
+	Result  json.RawMessage `json:"result,omitempty"`
+	Error   *RPCError       `json:"error,omitempty"`
+}
+
+// RPCError is a JSON-RPC 2.0 error object.
+type RPCError struct {
+	Code    int    `json:"code"`
+	Message string `json:"message"`
+}
+
+// InitializeResult is the server's response to the initialize request.
+type InitializeResult struct {
+	Capabilities ServerCapabilities `json:"capabilities"`
+	ServerInfo   *ServerInfo        `json:"serverInfo,omitempty"`
+}
+
+// ServerCapabilities advertises what the server supports.
+type ServerCapabilities struct {
+	// TextDocumentSync: 1 = Full (send entire document on every change).
+	TextDocumentSync int `json:"textDocumentSync"`
+}
+
+// ServerInfo identifies the server to the client.
+type ServerInfo struct {
+	Name    string `json:"name"`
+	Version string `json:"version,omitempty"`
+}
+
+// TextDocumentItem is a text document opened by the client.
+type TextDocumentItem struct {
+	URI        string `json:"uri"`
+	LanguageID string `json:"languageId"`
+	Version    int    `json:"version"`
+	Text       string `json:"text"`
+}
+
+// TextDocumentIdentifier references a text document by URI.
+type TextDocumentIdentifier struct {
+	URI string `json:"uri"`
+}
+
+// VersionedTextDocumentIdentifier includes a version number.
+type VersionedTextDocumentIdentifier struct {
+	URI     string `json:"uri"`
+	Version int    `json:"version"`
+}
+
+// TextDocumentContentChangeEvent is a single content change event.
+// With Full sync the Text field contains the complete new document text.
+type TextDocumentContentChangeEvent struct {
+	Text string `json:"text"`
+}
+
+// DidOpenTextDocumentParams is the params for textDocument/didOpen.
+type DidOpenTextDocumentParams struct {
+	TextDocument TextDocumentItem `json:"textDocument"`
+}
+
+// DidChangeTextDocumentParams is the params for textDocument/didChange.
+type DidChangeTextDocumentParams struct {
+	TextDocument   VersionedTextDocumentIdentifier  `json:"textDocument"`
+	ContentChanges []TextDocumentContentChangeEvent `json:"contentChanges"`
+}
+
+// DidSaveTextDocumentParams is the params for textDocument/didSave.
+type DidSaveTextDocumentParams struct {
+	TextDocument TextDocumentIdentifier `json:"textDocument"`
+	Text         *string                `json:"text,omitempty"`
+}
+
+// DidCloseTextDocumentParams is the params for textDocument/didClose.
+type DidCloseTextDocumentParams struct {
+	TextDocument TextDocumentIdentifier `json:"textDocument"`
+}
+
+// PublishDiagnosticsParams is the params for textDocument/publishDiagnostics.
+type PublishDiagnosticsParams struct {
+	URI         string       `json:"uri"`
+	Diagnostics []Diagnostic `json:"diagnostics"`
+}
+
+// Diagnostic is a lint finding expressed in LSP terms.
+type Diagnostic struct {
+	Range    Range  `json:"range"`
+	Severity int    `json:"severity"` // 1=Error, 2=Warning, 3=Information, 4=Hint
+	Code     string `json:"code,omitempty"`
+	Source   string `json:"source,omitempty"`
+	Message  string `json:"message"`
+}
+
+// Range is a zero-based line/character range within a text document.
+type Range struct {
+	Start Position `json:"start"`
+	End   Position `json:"end"`
+}
+
+// Position is a zero-based line and character offset.
+type Position struct {
+	Line      int `json:"line"`
+	Character int `json:"character"`
+}

internal/resolver/includes.go

@@ -133,6 +133,12 @@ func resolveLocalInclude(p *model.Pipeline, rawPath string, cfg fetcher.GitLabCo
 	absPath := filepath.Join(rootDir, relPath)
 	label := "local " + rawPath
 
+	// Guard against path traversal: reject any path that escapes rootDir.
+	rel, err := filepath.Rel(rootDir, absPath)
+	if err != nil || strings.HasPrefix(rel, "..") {
+		return []IncludeWarning{{Label: label, Err: fmt.Errorf("path escapes repository root: %s", rawPath)}}, nil
+	}
+
 	if visited[absPath] {
 		return nil, nil
 	}

internal/resolver/includes_test.go

@@ -6,6 +6,7 @@ import (
 	"net/http/httptest"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"git.k3nny.fr/glint/internal/fetcher"
@@ -332,6 +333,32 @@ func TestResolveLocalInclude_WithNestedIncludes(t *testing.T) {
 	}
 }
 
+func TestResolveLocalInclude_PathTraversal(t *testing.T) {
+	dir := t.TempDir()
+	p := &model.Pipeline{Jobs: map[string]model.Job{}, RawJobs: map[string]map[string]any{}}
+	// A path that escapes the repository root via "../.." must produce a warning,
+	// not silently read an arbitrary file.
+	warnings, _ := resolveLocalInclude(p, "../../etc/passwd", fetcher.GitLabConfig{}, dir, map[string]bool{}, 0)
+	if len(warnings) == 0 {
+		t.Fatal("expected warning for path traversal, got none")
+	}
+	if !strings.Contains(warnings[0].Err.Error(), "path escapes") {
+		t.Errorf("unexpected warning: %v", warnings[0])
+	}
+	if len(p.Jobs) != 0 {
+		t.Error("no jobs should be merged when path escapes root")
+	}
+}
+
+func TestResolveLocalInclude_PathTraversalWithLeadingSlash(t *testing.T) {
+	dir := t.TempDir()
+	p := &model.Pipeline{Jobs: map[string]model.Job{}, RawJobs: map[string]map[string]any{}}
+	warnings, _ := resolveLocalInclude(p, "/../../etc/shadow", fetcher.GitLabConfig{}, dir, map[string]bool{}, 0)
+	if len(warnings) == 0 {
+		t.Fatal("expected warning for path traversal via leading slash, got none")
+	}
+}
+
 // ── resolveRemoteInclude ──────────────────────────────────────────────────────
 
 func TestResolveRemoteInclude_Success(t *testing.T) {

testdata/insecure_remote_include.yml

@@ -0,0 +1,8 @@
+stages: [build]
+
+include:
+  - remote: http://ci-templates.example.invalid/template.yml
+
+build-job:
+  stage: build
+  script: echo hello