---
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: "1.0"

generatedBy: "1.2.0"

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

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>).

1. 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")
• Which artifact contains the tasks (typically "tasks" for spec-driven, check status for others)

1. 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

1. 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

1. Show current progress

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

1. 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

1. 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