ccx

A typed, append-only event log and resume system for Claude Code. Instead of asking an agent to maintain a free-form Session.md — which drifts, because prose always does — ccx records schema-validated events to Postgres, so resuming a session means querying ground truth rather than trusting a freshly generated self-summary. Its drift command reconciles the agent's completion claims against actual git state, which is the direct answer to "I already did that."

The design principle, from docs/design.md: prose drifts, schemas don't. Validation happens server-side and bad payloads are rejected.

How events get captured

• Mechanical — session start/end, task created/completed, and file writes are posted by Claude Code hooks invoking ccx hook <event> with the hook JSON on stdin. No agent cooperation required.

• Semantic — Plan, Decision, Question, and HumanFeedback are posted by the agent through the stdio MCP server.

Completion events carry evidence or they don't validate: a commit SHA if the intent produced code, a test command and exit code if tests ran.

Related MCP server: threadline-core

Layout

• packages/schema — Zod envelope + payload schemas

• packages/storage — Drizzle client, event append/query, digest, drift check

• packages/mcp-server — stdio MCP server (8 tools)

• packages/cli — ccx init|digest|tail|blocked|drift|replay|projects|hook

Proof

• 147 tests across 25 files — pnpm test

• Requires Docker: the storage suite spins up an ephemeral postgres:16-alpine testcontainer and applies migrations per run. Coverage is concentrated in schema (73) and storage (45); the MCP tool handlers are the thin spot.

Status

Phase 1 revised (hooks-based capture). 8 event types are implemented; Assumption, Discovery, Issue, Revert, and PlanComplete are reserved names deferred to Phase 2 — validating a payload for those throws. Plan 3 adds a SQLite local fallback.

Quick start

pnpm install && pnpm build

# 1. Create a Postgres database called `ccx`, then point ccx at it
printf 'database_url = "postgresql://user:pass@host:5432/ccx"\n' > ~/.ccx/config.toml
chmod 600 ~/.ccx/config.toml     # hooks read from here, not the environment

# 2. Apply migrations
psql "$(python3 -c "import tomllib,os;print(tomllib.load(open(os.path.expanduser('~/.ccx/config.toml'),'rb'))['database_url'])")" \
  -f packages/storage/drizzle/0001_*.sql

# 3. In any project repo
node <path-to-ccx>/packages/cli/dist/index.js init   # creates .ccx/project.toml

Then register the five hooks (SessionStart, SessionEnd, TaskCreated, TaskCompleted, and PostToolUse matching Write|Edit|MultiEdit|NotebookEdit) in ~/.claude/settings.json, each running node <path-to-ccx>/packages/cli/dist/index.js hook <event> with a 10s timeout and reading hook JSON from stdin. For the semantic tools, register the MCP server in ~/.claude.json.

License

MIT