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":"1.0","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>).

1a. Validate branch

Run git rev-parse --abbrev-ref HEAD to get the current branch.

• If the current branch is opsx/<change-name>: proceed.
• If the current branch is NOT opsx/<change-name>: STOP with error:

  "Must be on branch opsx/<change-name> to implement this change. Run: git checkout opsx/<change-name>"

1b. Retrieve implementation context from Dewey

Before implementing, query Dewey for relevant patterns:

• dewey_semantic_search with the task description to find similar implementations in other repos
• dewey_semantic_search_filtered with source_type: "web" to find relevant toolstack documentation
• dewey_search for convention pack references related to the task's domain

Use the retrieved context to follow established patterns and avoid reinventing solutions that already exist in the ecosystem.

If Dewey is unavailable, proceed with direct file reads of convention packs and local code examples.

Dewey Availability Tiers

Adjust context retrieval based on Dewey availability:

Tier 3 (Full Dewey): Use dewey_semantic_search, dewey_search, dewey_traverse, and dewey_semantic_search_filtered for comprehensive cross-repo and toolstack context.

Tier 2 (Graph-only, no embedding model): Use dewey_search and dewey_traverse for keyword-based and structural queries. Semantic search is unavailable.

Tier 1 (No Dewey): Fall back to direct file operations:

• Use the Read tool to read local specs, backlog items, and convention packs
• Use the Grep tool for keyword search across the codebase
• Reference .opencode/uf/packs/ for coding standards

All tiers produce valid results. Higher tiers provide richer cross-repo context but are never required.

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

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

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