scaffold

name	scaffold
description	Scaffolds the three-file context system (decisions.md, state.md, scratch.md) into a project. Use when setting up a new project's context layer, starting a context system, or when the user wants session context files alongside CLAUDE.md.
allowed-tools	Read, Write, Edit

Scaffold

Scaffold the three-file context system into the current project. These files sit alongside CLAUDE.md as the persistent context layer for working with Claude Code across sessions.

Existing files

!ls decisions.md state.md scratch.md .gitignore CLAUDE.md .claude/settings.json 2>/dev/null || echo "(none found)"

Files

File	Purpose	Git
decisions.md	Append-only log of major decisions	Tracked
state.md	Context bridge between sessions	Tracked
scratch.md	Ephemeral working notes for the current session	Ignored

Rules

0. This is a deterministic scaffold — no questions needed. When invoked, immediately check what exists and create what's missing. Do not ask for project type, stack, or preferences.
1. Never overwrite existing files. If decisions.md, state.md, or scratch.md already exists, skip it and tell the user.
2. Always update .gitignore. Append scratch.md if it's not already listed. Create .gitignore if it doesn't exist.
3. Always update CLAUDE.md with context-system instructions. If no CLAUDE.md exists, create a minimal one with a project title placeholder. Then append the context-system block below — but only if the sentinel <!-- context-system --> is not already present.
4. Install the session-start hook in .claude/settings.json. The hook injects state.md into context when a session starts fresh or after /clear. Create .claude/settings.json with the JSON below if it doesn't exist. If it exists, merge the SessionStart entry into the existing JSON without disturbing other settings. If a SessionStart hook whose command mentions state.md is already present, skip it and say so. Do not ask — install and report.
5. Do not scaffold anything else. No tech stack, linting, CI, or project structure. This is purely the context layer.

File contents

decisions.md

<!-- Append-only log of major decisions. Each entry: what was decided, when, why, and what was rejected. Versioned in git.

Entry format:

### YYYY-MM-DD — [Decision title]
**Status:** active
**Why:** [Rationale — what drove the decision]
**Rejected:** [What was considered and passed over, and why]

Status is `active` or `superseded`. An entry with no Status line is active. The Status line is the only part of an existing entry that may ever be edited. -->

# Decisions

state.md

<!-- Context bridge between sessions. Replace the contents of this file before ending a session so the next one can pick up without re-reading the entire codebase. -->

# State

## Where we ended
None

## What's working
None

## What's broken / in-progress
None

## Decided this session
None

## Next session should start with
None

## Landmines
None

scratch.md

<!-- Ephemeral working notes. Ideas, open questions, tangents during a session. Gitignored and wiped between sessions. -->

# Scratch

Fallback CLAUDE.md

Only create this if no CLAUDE.md exists:

# [Project Name]

Context-system block for CLAUDE.md

Append this to CLAUDE.md if the sentinel <!-- context-system --> is not already present:

<!-- context-system -->
## Context system

`state.md` is injected automatically at session start by a SessionStart hook — orient from it before acting. Run the orient skill for a full structured orientation with staleness checks.

Files:
- `state.md` — context bridge between sessions (tracked)
- `decisions.md` — append-only decision log (tracked)
- `scratch.md` — ephemeral working notes, wiped between sessions (gitignored)

Session-start hook for .claude/settings.json

Merge this into .claude/settings.json (create the file and the .claude directory if needed). If the file already has a hooks or SessionStart key, merge this entry in alongside what's there:

{
  "hooks": {
    "SessionStart": [
      {
        "matcher": "startup|clear",
        "hooks": [
          {
            "type": "command",
            "command": "[ -f state.md ] && { echo 'state.md from the last preserved session:'; cat state.md; } || true"
          }
        ]
      }
    ]
  }
}

Execution order

1. Use the existing files list above to determine which context files need to be created — skip any that already exist
2. If .gitignore exists, check whether scratch.md is already listed
3. Create missing files using the templates above
4. Append scratch.md to .gitignore if not already present — create .gitignore if it doesn't exist
5. Create fallback CLAUDE.md if needed
6. Append context-system block to CLAUDE.md if sentinel <!-- context-system --> not found
7. Install the session-start hook into .claude/settings.json — create or merge as needed, skip if a state.md hook is already present
8. Report what was created, what was skipped, and that the hook was installed