openspec-apply-change

name	openspec-apply-change
description	Implement tasks from an OpenSpec change. Use when the user wants to start implementing, continue implementation, or work through tasks.
license	MIT
compatibility	Requires openspec CLI.
metadata	{"author":"openspec","version":"1.1","generatedBy":"1.3.0"}

Implement tasks from an OpenSpec change.

Input: Optionally specify a change name. If omitted, check if it can be inferred from conversation context. If vague or ambiguous you MUST prompt for available changes.

Steps

0. Write apply-session start marker (required, added v1.1)

   Before reading any context files or performing implementation, signal that this apply session is skill-orchestrated. The PreToolUse hook installed per docs/rules/apply-skill-enforcement.rule.md BLOCKS the first Edit/Write on a slice's write_paths unless this marker exists for the current session.

   python .ai-playbook/scripts/openspec_apply_marker.py start --change-id "<name>" --skill-version 1.1
   

   The marker is appended to openspec/changes/<name>/.apply_log.jsonl (one JSONL record per session start; committed to git for audit). If the helper script is missing (consumer pre-v0.14.0 of ai-playbook), the hook is also missing — proceed; older consumers see no enforcement. Inform the user that their playbook bump is overdue.

   See: docs/rules/apply-skill-enforcement.rule.md §1 (marker contract) and §3 (break-glass via AIPLAYBOOK_APPLY_ENFORCE_OVERRIDE env).

1. Select the change

   If a name is provided, use it. Otherwise:

   • Infer from conversation context if the user mentioned a change
   • Auto-select if only one active change exists
   • If ambiguous, run openspec list --json to get available changes and use the AskUserQuestion tool to let the user select

   Always announce: "Using change: " and how to override (e.g., /opsx:apply <other>).

2. Check status to understand the schema

   openspec status --change "<name>" --json
   

   Parse the JSON to understand:

   • schemaName: The workflow being used (e.g., "spec-driven")
   • Which artifact contains the tasks (typically "tasks" for spec-driven, check status for others)

3. Get apply instructions

   openspec instructions apply --change "<name>" --json
   

   This returns:

   • Context file paths (varies by schema - could be proposal/specs/design/tasks or spec/tests/implementation/docs)
   • Progress (total, complete, remaining)
   • Task list with status
   • Dynamic instruction based on current state

   Handle states:

   • If state: "blocked" (missing artifacts): show message, suggest using openspec-continue-change
   • If state: "all_done": congratulate, suggest archive
   • Otherwise: proceed to implementation

4. Read context files

   Read the files listed in contextFiles from the apply instructions output. The files depend on the schema being used:

   • spec-driven: proposal, specs, design, tasks
   • Other schemas: follow the contextFiles from CLI output

4b. Preflight re-grep cited identifiers (added v0.11.0)

Per release-management.md §6.5 (pre-flight rebase) the worktree base is fresh, but proposal.md may have been written days earlier. Identifiers cited in the proposal (class names, function names, file paths, migration slot numbers, fact-kind enum values, ADR numbers) may have changed on main since the proposal landed. Apply silently against stale citations produces silent divergence.

Before starting implementation, re-grep every identifier the proposal/design/tasks cites:

1. Walk proposal.md + design.md + tasks.md and extract:

   • Quoted file paths (apps/api/src/.../foo.py).
   • Backticked class / function names (`IBClient`, `place_order`).
   • Migration slot numbers (0007_*, 0010_*).
   • ADR numbers (ADR-021).
   • Enum values mentioned in citations.

2. For each, run git grep -n "<identifier>" (or Grep tool) on main.

3. If any cited identifier returns 0 hits, surface as a divergence warning:

   ⚠ Citation drift detected
   proposal.md cites `FactKindEnum.MOMENTUM_SCORE` but no occurrence found on main.
   Likely renamed or removed in a parallel slice merged after this proposal landed.
   
   Options:
   1. Re-read the current main code to find the new name; update tasks.md citations.
   2. Re-open Gate D for design refresh (recommended for ≥3 drifted citations).
   3. Override with --skip-preflight-grep (logs deviation in retro carry-forward).
   

4. If 1-2 identifiers drifted, show the diff and let the user decide (small drift is normal across week-old proposals).

5. If ≥3 identifiers drifted OR a critical surface (migration slot, FK, public API) drifted, refuse to proceed without explicit --skip-preflight-grep flag.

This catches the failure mode surfaced 2026-05-06 in consumer-e (proposals written before parallel slices renamed cited classes) — without preflight grep, the worker AI would silently apply against drifted state and either fail at typecheck (best case) or ship broken code (worst case).

5. Show current progress

   Display:

   • Schema being used
   • Progress: "N/M tasks complete"
   • Remaining tasks overview
   • Dynamic instruction from CLI

6. Implement tasks (loop until done or blocked)

   For each pending task:

   • Show which task is being worked on
   • Make the code changes required
   • Keep changes minimal and focused
   • Mark task complete in the tasks file: - [ ] → - [x]
   • Continue to next task

   Pause if:

   • Task is unclear → ask for clarification
   • Implementation reveals a design issue → suggest updating artifacts
   • Error or blocker encountered → report and wait for guidance
   • User interrupts

7. On completion or pause, show status

   Display:

   • Tasks completed this session
   • Overall progress: "N/M tasks complete"
   • If all done: suggest archive
   • If paused: explain why and wait for guidance

Output During Implementation

## Implementing: <change-name> (schema: <schema-name>)

Working on task 3/7: <task description>
[...implementation happening...]
✓ Task complete

Working on task 4/7: <task description>
[...implementation happening...]
✓ Task complete

Output On Completion

## Implementation Complete

**Change:** <change-name>
**Schema:** <schema-name>
**Progress:** 7/7 tasks complete ✓

### Completed This Session
- [x] Task 1
- [x] Task 2
...

All tasks complete! Ready to archive this change.

Output On Pause (Issue Encountered)

## Implementation Paused

**Change:** <change-name>
**Schema:** <schema-name>
**Progress:** 4/7 tasks complete

### Issue Encountered
<description of the issue>

**Options:**
1. <option 1>
2. <option 2>
3. Other approach

What would you like to do?

Guardrails

• Keep going through tasks until done or blocked
• Always read context files before starting (from the apply instructions output)
• If task is ambiguous, pause and ask before implementing
• If implementation reveals issues, pause and suggest artifact updates
• Keep code changes minimal and scoped to each task
• Update task checkbox immediately after completing each task
• Pause on errors, blockers, or unclear requirements - don't guess
• Use contextFiles from CLI output, don't assume specific file names

Fluid Workflow Integration

This skill supports the "actions on a change" model:

• Can be invoked anytime: Before all artifacts are done (if tasks exist), after partial implementation, interleaved with other actions
• Allows artifact updates: If implementation reveals design issues, suggest updating artifacts - not phase-locked, work fluidly