Skill: agents-generator

[!WARNING] [Authorized Use Only] This skill writes or updates AGENTS.md, .agents/rules/, optional platform instruction files, and timestamped backups in the target project. Read the detected inputs and proposed outputs first, obtain approval before changing target files, and use it only inside the user's intended project scope.

When to Use

Use this skill when the user wants to:

• create a complete, project-specific AGENTS.md instead of generic agent rules;
• generate companion rules for detected frameworks, tests, databases, styling, or monorepo packages;
• create a minimal AGENTS.md, preview changes without writing, or update existing instructions after the stack changes.

Do not use it to invent conventions without inspecting the target project, to overwrite instructions outside the user's scope, or to treat generated guidance as a substitute for human review.

Generates a tailored AGENTS.md + .agents/rules/*.md for the target project — not a template with placeholders, but a living document that matches the project's real toolchain.

What you get

From a project that uses Bun + Next.js 16 + Tailwind + Vitest + Server Actions, the skill produces:

AGENTS.md
├── Setup commands: bun install, bun dev, bun run test:run, bun doctor
├── Verification Cycle: bunx tsc --noEmit → bun run lint → bun run test:run → bun doctor
├── Conventions: "Bun always. Plain TypeScript types + guards."
└── Architecture → .agents/rules/architecture.md

.agents/rules/
├── architecture.md       ← ASCII diagram with real directories, exact versions
├── frontend-patterns.md  ← Component rules, state locations, trust boundaries
├── server-actions.md     ← downloadVideo() flow, DownloadResult type, rate limiter
├── testing.md            ← "74 tests in 5 files", vitest commands, mock patterns
├── git-workflow.md       ← Conventional commits, pre-commit checks
└── sdd-workflow.md       ← Preflight defaults, post-apply verification

Rules NOT generated: backend.md (no NestJS), database.md (no ORM), i18n.md (hardcoded Spanish), forms.md (manual inputs), styling.md (Tailwind in frontend rules).

Activation Contract

Generate AGENTS.md + .agents/rules/*.md for the target project. Never guess — read the project's actual files first.

Mode selection

User says	Mode	Output
"simple AGENTS.md", "just the basics", "minimal"	Minimal	Single AGENTS.md (~30 lines, no rule files)
"full AGENTS.md", "with rules", "complete", or default	Full	AGENTS.md + .agents/rules/*.md
"update AGENTS.md", "refresh", "my stack changed"	Update	Diff existing, regenerate only what changed

Dry-run mode

If the user asks to "preview", "show what would change", "dry-run": run all detection but do NOT write files. Show detection summary, files that would be created, skipped rules, and sample output.

Hard Rules

• Read before writing, but never read secrets. Read package.json, non-secret config files, and directory structure before generating anything. Never open .env, .env.local, credential stores, or similarly secret-bearing files. Derive environment variable names only from .env.example placeholders and source references such as process.env.NAME, without reading or reporting values.
• Detect package manager FIRST. Check lockfiles: bun.lock→bun, pnpm-lock.yaml→pnpm, package-lock.json→npm, yarn.lock→yarn. NEVER default to npm. Every command uses the detected PM.
• Generate only what applies. No backend rules for frontend-only. No database rules without ORM.
• Do not execute project scripts by default. Package-manager scripts are repository-controlled shell entry points. Detect and document candidate format/lint commands, but do not run them unless the user separately requests execution after the exact script body and invoked tooling have been reviewed.
• Validate commands. Every command in output must exist as a script key in package.json.
• No placeholders. Scan output for {{, TODO, add here, .... Reject if any remain.
• Backup first. If files exist, copy to .agents/backups/ with timestamp.

Execution Steps

Common

1. git rev-parse --show-toplevel → project root.
2. Detect package manager FIRST: check lockfiles. bun.lock→bun, pnpm-lock.yaml→pnpm, package-lock.json→npm, yarn.lock→yarn. Never default to npm.
3. Read package.json (scripts, deps, workspaces). Save scripts for validation.
4. Read non-secret config files and explore directory structure. Exclude .env* files other than placeholder-only .env.example; never read secret values.
5. Select mode (ask if ambiguous).

Full mode

1. Read assets/agents-full.md — this is the AGENTS.md structure with all sections and filling rules.
2. Read project files and fill every placeholder with real data. Never use generic text.
3. Generate AGENTS.md at project root. Wrap cont