name: handoff type: workflow description: "Generates the lightweight 3-field handoff summary for cross-domain work and optionally persists a formal handoff artifact for High-risk transfers." argument-hint: "<from-agent> <to-agent> <artifact> [task_id] [--risk Low|Medium|High] [--status complete|partial|draft] [--criteria "crit1" "crit2"] [--formal]" user-invocable: true allowed-tools: Read, Write, Bash effort: 1 when_to_use: "Run when a cross-domain handoff needs an explicit 3-field summary, or when a High-risk transfer needs a durable handoff file in addition to the summary."

Handoff

Generate the lightweight handoff summary (what was built, what's missing, acceptance criteria) and, when needed, save a formal handoff artifact to .tasks/handoffs/. The receiver verifies the summary before starting work.

Steps

1. Parse arguments

Extract from $ARGUMENTS:

If from-agent, to-agent, or artifact are missing, print usage and stop:

Usage: /handoff <from-agent> <to-agent> <artifact> [task_id] \
                [--risk Low|Medium|High] \
                [--status complete|partial|draft] \
                [--criteria "criterion 1" "criterion 2"] \
                [--formal]

Example:
  /handoff backend-developer qa-engineer src/api/auth.ts 042 \
           --risk Medium --criteria "POST /auth returns 201" "Invalid creds → 401"

Schema reference: .claude/docs/handoff-schema.md

2. Validate agents

Check that <from-agent>.md and <to-agent>.md exist in .claude/agents/. If either is missing, warn but continue:

⚠️  Agent "<name>" not found in .claude/agents/ — check spelling.

3. Resolve task_id and context_snapshot

• If task_id was provided, check if .tasks/checkpoints/<task_id>.md exists. If yes, set context_snapshot to that path.
• If task_id was NOT provided, scan .tasks/checkpoints/ for the most recently modified .md file (excluding .gitkeep) and use it as a suggestion.
• If no checkpoint exists, set context_snapshot to null.

4. Collect acceptance criteria

If --criteria flags were provided, use them directly.

If no criteria were provided, prompt:

📋 Enter acceptance criteria for this handoff (one per line, blank line to finish):
>

Require at least 1 criterion. Reject vague criteria and ask for a rewrite:

• Contains "works correctly", "looks good", "should be fine", "seems OK" → reject
• Must describe a concrete, testable outcome

5. Get session info

Run git branch --show-current to get the current branch for the session field. Get current ISO timestamp for ts.

6. Generate handoff summary

Build the 3-field summary per .claude/docs/handoff-schema.md:

## Handoff Summary
- What was built: <artifact> is available with its current behavior/status
- What's missing: remaining gaps, partial work, or "Nothing blocking in current scope"
- Acceptance criteria:
  - <crit1>
  - <crit2>

Also prepare the formal JSON payload only when:

• risk_tier is High and the handoff crosses domains, or
• the caller passes --formal

When the formal artifact is needed, use this JSON:

{
  "from": "<from-agent>",
  "to": "<to-agent>",
  "task_id": "<task_id or null>",
  "artifact": "<artifact>",
  "artifact_status": "<status>",
  "acceptance_criteria": ["<crit1>", "<crit2>"],
  "context_snapshot": "<path or null>",
  "risk_tier": "<risk>",
  "ts": "<ISO>",
  "session": "<branch>"
}

7. Save formal contract when required

If formal persistence is required, write to .tasks/handoffs/<from-agent>-to-<to-agent>-<task_id>.json. If task_id is null, use timestamp: .tasks/handoffs/<from-agent>-to-<to-agent>-<ts-compact>.json.

If formal persistence is not required, do not create a file. The markdown handoff summary is the default artifact.

8. Ledger entry (Medium / High risk only)

If risk_tier is Medium or High, append to production/traces/decision_ledger.jsonl:

{"ts":"<ISO>","session":"<branch>","agent_id":"<from-agent>","task_id":"<task_id>","request":"Handoff to <to-agent>","reasoning":"Artifact <artifact> is <status> — transferring ownership","choice":"Handoff summary prepared","outcome":"pass","risk_tier":"<risk>","duration_s":0}

9. Display and confirm

Print the summary first, then note whether a durable file was written:

🤝 Handoff Summary Generated
━━━━━━━━━━━━━━━━━━━━━━━━━━

  From  : @<from-agent>
  To    : @<to-agent>
  Task  : <task_id>
  File  : <artifact> [<status>]
  Risk  : <risk_tier>

  What was built:
    <one-line built summary>

  What's missing:
    <one-line gap summary>

  Acceptance Criteria:
    - <criterion 1>
    - <criterion 2>

  Context Snapshot: <path or "none">
  [if formal]: Saved to .tasks/handoffs/<filename>.json
  [if Medium/High]: Ledger entry written.

📨 Ready to hand off. @<to-agent> should verify the summary above
   before starting work on <artifact>.

Receiver Protocol

When an agent receives a handoff, it must:

1. Read the 3-field summary (and the formal file if one exists)
2. Verify each acceptance_criterion against the artifact
3. If all criteria pass → begin work
4. If any criterion fails → do NOT start work; reply to sender with:

❌ Handoff rejected — criterion failed:
   "<failing criterion>"
   Artifact: <artifact>
   Action needed: <specific fix required>

Quick Examples

# Basic handoff — backend to QA
/handoff backend-developer qa-engineer src/api/auth.ts 042

# With explicit criteria and risk
/handoff frontend-developer lead-programmer src/components/LoginForm.tsx 055 \
  --risk Low --status partial \
  --criteria "Form renders without errors" "Submit disabled when fields empty"

# Draft handoff for review before final delivery
/handoff data-engineer backend-developer src/db/migrations/004_add_users.sql 031 \
  --status draft --risk High --formal \
  --criteria "Migration runs without error on empty DB" "Down migration restores schema"