# Openspec Apply Change

> Implement tasks from an OpenSpec change. Use when the user wants to start implementing, continue implementation, or work through tasks.

- **Type:** Skill
- **Install:** `agentstack add skill-bcgen-skills-openspec-apply-change`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [BCGen](https://agentstack.voostack.com/s/bcgen)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [BCGen](https://github.com/BCGen)
- **Source:** https://github.com/BCGen/skills/tree/main/.claude/skills/openspec-apply-change
- **Website:** https://skills.sh/BCGen/skills

## Install

```sh
agentstack add skill-bcgen-skills-openspec-apply-change
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

Implement tasks from an OpenSpec change.

**Store selection:** If the user names a store (a store is a standalone OpenSpec repo registered on this machine) or the work lives in one, run `openspec store list --json` to discover registered store ids, then pass `--store ` on the commands that read or write specs and changes (`new change`, `status`, `instructions`, `list`, `show`, `validate`, `archive`, `doctor`, `context`). Other commands do not take the flag. Hints printed by commands already carry the flag; keep it on follow-ups. Without a store, commands act on the nearest local `openspec/` root.

**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 `).

2. **Check status to understand the schema**
   ```bash
   openspec status --change "" --json
   ```
   Parse the JSON to understand:
   - `schemaName`: The workflow being used (e.g., "spec-driven")
   - `planningHome`, `changeRoot`, and `actionContext`: planning scope and edit constraints
   - Which artifact contains the tasks (typically "tasks" for spec-driven, check status for others)

3. **Get apply instructions**

   ```bash
   openspec instructions apply --change "" --json
   ```

   This returns:
   - `contextFiles`: artifact ID -> array of concrete 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 every file path listed under `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

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:  (schema: )

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

Working on task 4/7: 
[...implementation happening...]
✓ Task complete
```

**Output On Completion**

```
## Implementation Complete

**Change:** 
**Schema:** 
**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:** 
**Schema:** 
**Progress:** 4/7 tasks complete

### Issue Encountered

**Options:**
1. 
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

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [BCGen](https://github.com/BCGen)
- **Source:** [BCGen/skills](https://github.com/BCGen/skills)
- **License:** MIT
- **Homepage:** https://skills.sh/BCGen/skills

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-bcgen-skills-openspec-apply-change
- Seller: https://agentstack.voostack.com/s/bcgen
- Browse the marketplace: https://agentstack.voostack.com/browse

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