AI Context File Generator
The Signal Gate
Research shows auto-generated context files reduce AI task success by ~3% and increase token costs by 20% (ETH Zurich, Feb 2026). Less is more.
The test for every line: Would removing this cause the AI to make a mistake? If not, cut it.
Include (Non-Discoverable)
- Non-obvious conventions (import order, naming deviations, spelling locale)
- Hard constraints ("never use
any", "always usedirenv exec") - Key commands (test, build, deploy, lint)
- Security rules and environment quirks
Exclude (Discoverable)
Directory listings, dependency lists, architecture overviews, framework conventions, API patterns visible in source, key file tables — agents discover all of these by reading the codebase.
Describe the end state you want, not step-by-step instructions. Consider fixing root causes rather than documenting workarounds (Osmani, 2026).
Line Budgets
| File | Target | Hard Max |
|---|---|---|
| AGENTS.md | Under 120 lines | 160 lines |
| CLAUDE.md bridge | 10-20 lines | 80 lines |
| Other bridge files | 10-20 lines | 60 lines |
Supported Context Files
| File | Role | Purpose |
|---|---|---|
AGENTS.md |
Canonical | Shared identity, commands, conventions, constraints, security notes, monorepo guidance |
CLAUDE.md |
Thin bridge | Claude-specific rules + @AGENTS.md import |
.cursor/rules/agents.mdc |
Modern Cursor (default) | Frontmatter description, globs, alwaysApply; body imports AGENTS.md |
.cursorrules |
Legacy Cursor | Only emitted if already present; ignored by current Cursor in Agent mode |
.github/copilot-instructions.md |
Optional | Copilot loads AGENTS.md natively (Aug 2025); only emit for tool-specific scoping |
.windsurfrules |
Compatibility | Windsurf rule activation/metadata only |
.clinerules/agents.md |
Modern Cline (default) | Directory mode; supports paths: frontmatter for path-scoped rules |
.clinerules |
Legacy Cline | Flat-file fallback when already present |
GEMINI.md |
Compatibility | Gemini-specific discovery or extension notes only |
Format details and frontmatter examples live in SKILL-reference.md.
Context file vs memory: Context files contain instructions for the agent (shared via git). Memory files (MEMORY.md, agent-memory/) are notes by the agent (local only). Promote recurring memory insights to the appropriate context file.
Generation Workflow
- Detect project profile — scan manifests for language, framework, test runner, linter, CI/CD
- Extract non-discoverable conventions — import order, naming patterns, commands, security rules, environment quirks
- Generate
AGENTS.mdfirst — all shared commands, conventions, rules, and security notes in one canonical file (~120 lines; omit Project Structure, architecture, dependency dumps, key-file tables) - Generate bridge files — apply the Signal Gate again. CLAUDE.md uses
@AGENTS.mdplus Claude-specific additions (.claude/rules/references, key file pointers, path-scoped guidance). Other bridges reference or subset AGENTS.md and add only tool-specific fields. Cline may add a## Before Committingchecklist..windsurfrulesandGEMINI.mdare compatibility bridges — keep them especially lean.
Modes
init — Bootstrap new project
Scan codebase, generate AGENTS.md plus bridges that don't already exist: CLAUDE.md (uses @AGENTS.md), .cursor/rules/agents.mdc (modern Cursor), .windsurfrules, .clinerules/agents.md (directory mode), GEMINI.md. Copilot bridge optional (Copilot loads AGENTS.md natively). Skip files that already exist. Offer Context Guard hooks (Claude Code only), run audit pass, report summary.
Optional flag — --scaffold=six-section: Generate AGENTS.md using the GitHub Blog Apr 2026 six-section template (commands · testing · project structure · code style · git workflow · boundaries). Opt-in only — existing files are not migrated.
update — Incremental drift patching
Compare context file commits vs source commits. Classify changes (scripts → Commands, configs → Conventions, renames → paths). Update AGENTS.md first, then only the bridge files whose tool-specific sections or references changed. Apply surgical edits using Edit — preserve human customisations.
audit — Staleness check
Check version accuracy, command accuracy, stale paths, bridge contradictions against AGENTS.md, new untracked conventions, MEMORY.md drift, Context Guard health.
promote — MEMORY.md → CLAUDE.md
Find convention-like patterns in MEMORY.md ("Always", "Never", "Use", "Prefer"). Cross-reference against CLAUDE.md. Present candidates. Append promoted insights using Edit.
AGENTS.md Spec & Anti-Patterns
Tracks agents.md spec v1.0 via upstream-versions.json; check-upstream Action flags drift. Don't implement draft v1.1 until stable. Don't include discoverable content (trees, deps, architecture), framework docs, secrets, or session-specific state. Always curate auto-generated files.
Platform Notes
AGENTS.md auto-load: Codex CLI, OpenCode, Cursor, Windsurf, Cline, and Copilot load AGENTS.md natively. Claude Code requires @AGENTS.md in CLAUDE.md. Gemini CLI is configurable via context.fileName in settings.json.
Modern Cursor / Cline / Copilot (2026): Cursor uses .cursor/rules/*.mdc with frontmatter; flat .cursorrules is ignored in Agent mode. Cline uses the .clinerules/ directory with optional path-scoped frontmatter. Copilot's coding agent loads AGENTS.md natively (Aug 2025), so the Copilot bridge is optional. Format details and frontmatter examples live in SKILL-reference.md.
Hooks: Context Guard hooks are available on Claude Code (12 events), Gemini CLI (11), Copilot (8, preview), Cursor (4+), Cline (3), and Codex CLI (2, experimental). See the context-guard skill for per-platform setup.
Standalone verification: Run bin/context-verify.sh on any platform for 0-100 health scoring without a plugin system.
Advanced Reference (Claude Code)
For agent/skill frontmatter fields, variable substitution, dynamic context injection, bundled resources, CLAUDE.md advanced features (@import, directory walking, claudeMdExcludes, managed policy), rules system (path-scoped rules, recursive discovery, symlinks), and plugin system (installation scopes, output styles, plugin settings), load the companion reference: SKILL-reference.md
Source: littlebearapps/contextdocs — distributed by TomeVault.