openspec-apply-change

Implement tasks from an OpenSpec change.

Input: Optionally specify a change name. If omitted, MUST prompt for available changes.

Steps

1. •

   If no change name provided, prompt for selection

   Run openspec list --json to get available changes. Use the AskUserQuestion tool to let the user select.

   Show changes that are implementation-ready (have tasks artifact). Include the schema used for each change if available. Mark changes with incomplete tasks as "(In Progress)".

   IMPORTANT: Do NOT guess or auto-select a change. Always let the user choose.

2. •

   Check status to understand the schema

   bash

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

   Parse the JSON to understand:

   • •schemaName: The workflow being used (e.g., "spec-driven", "tdd")
   • •Which artifact contains the tasks (typically "tasks" for spec-driven, check status for others)
3. •

   Get apply instructions

   bash

   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
   • •tdd: spec, tests, implementation, docs
   • •Other schemas: follow the contextFiles from CLI output
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