fix(templates): deduplicate apply skill and command instructions

src/core/templates/workflows/apply-change.ts

@@ -6,13 +6,14 @@
  */
 import type { SkillTemplate, CommandTemplate } from '../types.js';
 
-export function getApplyChangeSkillTemplate(): SkillTemplate {
-  return {
-    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.',
-    instructions: `Implement tasks from an OpenSpec change.
+// ── Shared instruction body ───────────────────────────────────────────────────
+// Single source of truth for apply workflow instructions.
+// Both the skill template and command template reference this constant,
+// eliminating content drift between the two generated files.
+// See: https://github.com/Fission-AI/OpenSpec/issues/1139
+const APPLY_INSTRUCTIONS = `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.
+**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**
 
@@ -47,7 +48,7 @@ export function getApplyChangeSkillTemplate(): SkillTemplate {
    - Dynamic instruction based on current state
 
    **Handle states:**
-   - If \`state: "blocked"\` (missing artifacts): show message, suggest using openspec-continue-change
+   - If \`state: "blocked"\` (missing artifacts): show message, suggest using \`/opsx:continue\`
    - If \`state: "all_done"\`: congratulate, suggest archive
    - Otherwise: proceed to implementation
 
@@ -119,7 +120,7 @@ Working on task 4/7: <task description>
 - [x] Task 2
 ...
 
-All tasks complete! Ready to archive this change.
+All tasks complete! You can archive this change with \`/opsx:archive\`.
 \`\`\`
 
 **Output On Pause (Issue Encountered)**
@@ -157,7 +158,13 @@ What would you like to do?
 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`,
+- **Allows artifact updates**: If implementation reveals design issues, suggest updating artifacts - not phase-locked, work fluidly`;
+
+export function getApplyChangeSkillTemplate(): SkillTemplate {
+  return {
+    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.',
+    instructions: APPLY_INSTRUCTIONS,
     license: 'MIT',
     compatibility: 'Requires openspec CLI.',
     metadata: { author: 'openspec', version: '1.0' },
@@ -170,153 +177,6 @@ export function getOpsxApplyCommandTemplate(): CommandTemplate {
     description: 'Implement tasks from an OpenSpec change (Experimental)',
     category: 'Workflow',
     tags: ['workflow', 'artifacts', 'experimental'],
-    content: `Implement tasks from an OpenSpec change.
-
-**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 use the **AskUserQuestion tool** to let the user select
-
-   Always announce: "Using change: <name>" and how to override (e.g., \`/opsx:apply <other>\`).
-
-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")
-   - \`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 "<name>" --json
-   \`\`\`
-
-   This returns:
-   - \`contextFiles\`: artifact ID -> array of concrete file paths (varies by schema)
-   - 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 \`/opsx:continue\`
-   - If \`state: "all_done"\`: congratulate, suggest archive
-   - Otherwise: proceed to implementation
-
-   **Workspace guard:** If status JSON reports \`actionContext.mode: "workspace-planning"\` and \`allowedEditRoots\` is empty, explain that full workspace apply is not supported in this slice. Treat linked repos and folders as read-only context, ask the user to select an affected area through an explicit implementation workflow, and STOP before editing files.
-
-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: <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! You can archive this change with \`/opsx:archive\`.
-\`\`\`
-
-**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`
+    content: APPLY_INSTRUCTIONS,
   };
-}
+}