/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. Also use when the user says "openspec apply", "opsx apply", or "openspec implement".
allowed-tools: Bash(openspec:*)
license: MIT
compatibility: Requires openspec CLI.
metadata:
  author: openspec
  version: "1.0"
  generatedBy: "1.13.1"

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 <id>` on the commands that read or write specs and changes (`new change`, `status`, `instructions`, `list`, `show`, `validate`, `archive`, `doctor`, `context`, `schemas`, `view`). Once selected, treat `--store <id>` as sticky for the rest of the workflow. Every unscoped example of those commands below is shorthand: before running it, append the flag. For example, run `openspec status --change "<name>" --json --store "<id>"`, not the unscoped form shown below. 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.

**Project check:** These steps expect a project that already uses OpenSpec. Before the first step that writes anything (`new change`, `archive`, `sync specs`, or authoring an artifact file), confirm the project has a root: run `openspec list --json` (with `--store <id>` when a store is selected, since the store is then the root) and read `root`. A root object means the project is set up. `"root": null` means it is not - there is no `openspec/` directory here, and a write such as `openspec new change` would create one as a side effect. The command also exits non-zero, which is that answer rather than a broken CLI, so read the JSON instead of retrying or working around it.

One `"root": null` is not about setup: when a `status` error message starts with `Declared in` or `Invalid store declaration in` and names this project's `openspec/config.yaml` (or `config.yml`), the project does use OpenSpec through a store it declares, which this machine cannot resolve (the store is not registered, or the `store:` line is malformed). Do not treat it as uninitialized and skip the branches below: stop before writing and show the user that error's `message` and `fix`.

Otherwise, with no root, what happens next depends on how this workflow was reached:

• **Auto-selected**: you chose this workflow yourself, without the user naming OpenSpec, naming this skill, or running its slash command. Stop using OpenSpec and answer the request normally, as you would with no OpenSpec installed. Do not ask them to set anything up and do not mention OpenSpec setup.
• **Explicit OpenSpec request**: the user named OpenSpec, named this skill, or ran its slash command. Stop before writing and ask how to proceed: set this project up (`openspec init`), target a store they already have (`--store <id>`), or continue without OpenSpec for this request. Wait for their answer.

In both branches, never create the root as a side effect: do not run `openspec init` until the user asks for it, do not hand-create `openspec/` files, and do not let a command create it.

**Input**: Optionally specify a change name (e.g., `/opsx:apply add-auth`). 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 ask the user to select one

Always announce: "Using change: <name>" 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")
• `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**

   openspec instructions apply --change "<name>" --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
• Optional `context`: current required project instruction input from the selected root
• Optional `operationGuidance`: current advisory guidance for apply
• `missingArtifacts` (when present): required artifact ids with no output

**Handle states:**

• If `state: "blocked"`: show the message and pause implementation.
• If `missingArtifacts` is non-empty: suggest completing the missing artifacts. Run `openspec status --change "<name>" --json`, select the next `ready` artifact (not `skipped` or `blocked`), and use `openspec instructions "<artifact-id>" --change "<name>" --json` for its rules and template. Keep the selected `--store <id>` on both commands.
• Otherwise, follow the CLI instruction to create or repair the schema-configured tracking file from existing planning artifacts. Do not assume another artifact is ready or start implementation while blocked.
• If `state: "all_done"`: congratulate, suggest archive
• Otherwise: proceed to implementation

Treat `context` as a required prompt-level input. Read and consider it, and apply relevant project facts, conventions, and constraints while implementing. Treat `operationGuidance` as optional additive adv