implement-plan

name	implement-plan
description	Execute (or resume) an implementation plan stored in .implementation-plan.md. Use when the user types /implement-plan, asks to "resume implementation", or "continue the plan". Reads .implementation-plan.md, picks up at the first uncompleted step in the Execution Progress checklist, and dispatches a Sonnet agent to finish the work.
version	1.0.0
user_invocable	true

/implement-plan — Resume or Execute an Implementation Plan

Execute (or resume) the plan stored in .implementation-plan.md. Picks up at the first unchecked item in the ## Execution Progress checklist — completed steps are never re-run.

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Step 0: Preflight Check

Run the shared preflight script to verify prerequisites before doing any work:

bash .claude/skills/shared/preflight.sh

Stop on failure — do not proceed.

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Step 1: Locate the Plan

Verify that .implementation-plan.md exists.

• If not found: abort with — "No .implementation-plan.md found. Run /implement <issue-number> first, or create the file manually."
• If found: read the full file. Extract the issue number from the <!-- issue: #N --> comment on the first line.
  • If the comment is missing, warn: "No issue number found in .implementation-plan.md — proceeding in plan-only mode."

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Step 2: Cross-Reference Current Issue (Best-Effort)

Check whether .current-issue.md exists:

• Exists and matches the same issue number → use it as additional context throughout.
• Exists with a different issue number → stop:

  ".current-issue.md is for issue #X but .implementation-plan.md is for issue #N. These are out of sync — delete the stale file or run /implement <issue-number> to start fresh."

• Does not exist → proceed in plan-only mode without warning.

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Step 3: Locate or Initialize Execution Progress

Look for a ## Execution Progress section in .implementation-plan.md.

• If missing: append it to the file using the Edit tool:

  ## Execution Progress
  - [ ] Plan steps executed
  - [ ] Implementation reported
  

• Find the first unchecked item in the ## Execution Progress checklist.

  • If all items are checked: announce "Plan already complete — run /commit when ready." and exit.
  • If at least one is unchecked: proceed to Step 4.

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Step 4: Dispatch Sonnet Subagent

Use the Agent tool with subagent_type="general-purpose" and model="sonnet":

"Implement (or resume implementing) GitHub issue #.

Read .implementation-plan.md for the full plan and .current-issue.md (if it exists) for issue context.

The plan contains a ## Execution Progress checklist near the bottom. Find the first unchecked item and resume from there — do NOT redo completed steps. As you complete each item, use the Edit tool to mark its checkbox [x] in .implementation-plan.md.

Report what was done plus anything needing human review. Do not commit."

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Step 5: Report Back

Re-read .implementation-plan.md after the subagent completes.

• If any Execution Progress items remain unchecked: report them as "Remaining work" and instruct the user to re-run /implement-plan to continue.
• If all items are checked: report "Implementation complete. Review the changes, then run /commit when ready."