Set Up or Update Project Context Infrastructure

Context is organized in three tiers:

Central principle: context must earn its token cost. Only include knowledge that agents cannot discover by exploring the codebase with Grep, Glob, and Read.

AGENTS.md is the only guidance file. Don't create a CLAUDE.md: Claude Code reads AGENTS.md natively when no CLAUDE.md or CLAUDE.local.md is present, so a symlink or copy only adds a second name. A CLAUDE.md is justified only for Claude-specific content the user wants kept — then it is @AGENTS.md followed by that content, never a copy.

Input

Optional project root path ($ARGUMENTS; defaults to cwd). Optional: -- <additional context> for execution guidance.

Process

Step 1: Assess What Exists

Scan the project root for AGENTS.md, CLAUDE.md, README.md, and docs/. The file state determines the work: nothing exists → generate from scratch; legacy CLAUDE.md without AGENTS.md → migrate it to AGENTS.md, then update; AGENTS.md exists → audit and update. A CLAUDE.md that is a symlink to or copy of AGENTS.md is removed in Step 7.

Step 2: Explore the Codebase

Explore structure, tooling, CI/CD, and docs (skip for greenfield projects). Classify each finding as discoverable (agents can find it themselves) or requires documentation (decisions, conventions, failure modes) — only the second category belongs in context files.

Assess agent readiness: feedback loops (tests, linter, build cycle speed), module structure, app legibility, known risks. A check that prints pages on success fills the agent's context with noise: under feedback loops, name the tool's quiet flag when it has one, or leave a <!-- TODO --> for a wrapper that prints one line on success and everything on failure.

Also prepare unattended shipping: a fresh-checkout step, a run recipe, and the ## Unattended Shipping section, per unattended-shipping, which says what happens in which step.

Step 3: Audit Existing Guidance

When guidance files already exist, score each section:

Present an audit report grouped by impact and get user confirmation via AskUserQuestion before applying changes.

Step 4: Gather Project Information

Use AskUserQuestion for what code cannot reveal: core principles, repeated failure modes, and domain invariants — plus anything ambiguous from exploration, gaps surfaced by the Step 3 audit, and the fresh-checkout step, run recipe parts, and peer reviewer that discovery left open. Never ask what's discoverable from code. Incorporate any trailing context when deciding what to ask.

Step 5: Generate or Update AGENTS.md

Create or update AGENTS.md. Keep it under ~200 lines — length comes from content that passes the undiscoverability test, so a small project's file is short. See agents-md-template.md for the structure. When migrating, fold accepted legacy content in and remove the old file in Step 7.

Step 6: Generate or Update Tier 2 — docs/

Create docs/architecture.md (design decisions, data flow, module responsibilities) and docs/pr-workflow.md (branch naming, PR checklist, review process); offer further docs (development, coding-guidelines, testing, domain-specific) via AskUserQuestion only when exploration surfaced content that warrants them. Every doc must pass the undiscoverability test — an empty doc wastes context.

Step 7: Remove Redundant CLAUDE.md and Update .gitignore

Delete a CLAUDE.md that is a symlink to AGENTS.md, a copy of it, or legacy content now migrated into it (git rm when tracked). If it still holds content that isn't in AGENTS.md, ask the user via AskUserQuestion before deleting it. If it holds Claude-specific content the user wants to keep, reduce it to @AGENTS.md plus that content instead. If a CLAUDE.local.md exists, tell the user: Claude Code skips AGENTS.md while one is present. When you remove a CLAUDE.md, mention that some Claude Code versions and setups read only CLAUDE.md (which ones); for those, the fix is a CLAUDE.md containing @AGENTS.md. Append missing stack-appropriate entries to .gitignore — never overwrite an existing one.

Step 8: Create Human-Facing Files

Create README.md if it doesn't exist (project description, quick start, docs links — for humans, not agent context). If one exists, ask via AskUserQuestion: replace, merge, or keep?

Step 9: Commit

Stage and commit the new/modified files: docs: set up agentic context infrastructure (or docs: update context infrastructure when updating). Skip the commit if unrelated staged changes exist or generated files have unresolved questions.

Step 10: Summarize

Report what was created/changed — see output-format.md. Include tier status with line counts, agent readiness assessment, and next steps.

Guidelines

• Undiscoverability test — "Would an agent find this by exploring?" If yes, don't write it.
• Signal over volume — tables beat paragraphs; omit empty sections.
• Tier discipline — AGENTS.md stays under ~200 lines. Past 200, move to Tier 2.
• Edge cases — monorepos: suggest per-package AGENTS.md. No tests/CI: mention as next steps.

Related Skills

Next step: Use forge-create-issue to plan your first piece of work — or forge-shape if the idea is still rough and needs convergent questioning first.

Example Usage

/forge-setup-project
/forge-setup-project /path/to/project
/forge-setup-project -- keep the setup lean and call out missing feedback loops