Implement Plan

Execute an implementation plan file.

Task Tracking

At the start, use TaskCreate to create a task for each step:

1. Resolve and read the plan file
2. Read context files
3. Run /implement skill
4. Update plan status

Step 1: Resolve and Read the Plan File

Determine which plan file to implement using these rules in order:

1. Explicit path — If an absolute or relative path was passed and that file exists, use it
2. Explicit slug — If a slug was passed (e.g., add-image-cache), resolve to .turbo/plans/<slug>.md if that file exists
3. Single file — Glob .turbo/plans/*.md. If exactly one plan exists, use it
4. Most recent — If multiple plans exist, use the most recently modified
5. Legacy fallback — If .turbo/plans/ does not exist but .turbo/plan.md exists, use it
6. Nothing found — If no rule above resolved to an existing file, tell the user to run /turboplan and stop. When a slug or path was passed but no file matched it, say which one was tried

If multiple plans exist and the most-recent choice is non-obvious (e.g., several plans were modified within the same minute), use AskUserQuestion to let the user pick from the candidates.

State the resolved plan path before continuing, then read the file.

Unless an explicit path or slug was passed, confirm the resolved plan still describes work that remains to be done:

• Already implemented — the frontmatter status: is done
• Waiting on a gate — the plan's Context states a gate that must pass before its work can start

When a signal fires, output it as text. Then use AskUserQuestion to offer:

• Implement anyway — the marker is stale, or the gate has passed
• Pick another plan — resolve to a different file under .turbo/plans/, then confirm that plan against these same signals
• Leave it unimplemented — the plan needs revising first, or its gate has not passed

On Leave it unimplemented, tell the user to bring the plan current with /refine-plan and run this skill again, or, for a plan whose gate has not passed, to run this skill again once it has. Mark the remaining implement steps deleted, then use the TaskList tool and proceed to any remaining task.

Step 2: Read Context Files

The read list, every file to read in full:

• Every file listed in the plan's Context Files section
• Files the user referenced in their original request (if any)
• Every file path the plan references in the Context, Pattern Survey, and Implementation Steps sections

Project the read's share of the context window before the bulk of it. With one Bash call, get the size in bytes of each read-list file that exists, and their total. Call the mcp__context-level__read tool, then read the plan's Context Files. Once those reads have returned, call the tool again. While the reading has dropped fewer than five percentage points and read-list files remain unread, read a further batch and call the tool again. The projection is the drop from the first reading to the last, multiplied by the total bytes over the bytes read so far.

When the projection is above 25%, output as text that reading the plan's files is projected to take that share of the context window, with the number of files still unread. Then use AskUserQuestion to ask how to implement the plan:

• Implement in this session — this session reads the remaining files and implements every step itself, and will likely need to compact before QA. Mark it recommended when the projection is 50% or less.
• One subagent per step — the remaining files stay unread here, and each Implementation Step goes to a fresh subagent that reads what its step names. Every subagent gathers its own context, so the run takes longer and uses more tokens overall. Mark it recommended when the projection is above 50%.

Read the remaining read-list files unless the answer was One subagent per step.

Step 3: Run /implement Skill

Run the /implement skill. The plan file, its file references, and its Verification section are already in conversation context from Step 1. When Step 2 settled on one subagent per step, pass that choice along.

Step 4: Update Plan Status

After /implement completes, set the plan's frontmatter status: to done with the Edit tool. If the plan is the legacy .turbo/plan.md without frontmatter, skip the status update.

When that edit is refused while this session runs inside a linked worktree, report that the status update was not applied and name the edit to make from a session that can write to the main checkout: status: done in the resolved plan path.

When the plan's Context names a larger source it implements part of (an assessment, a backlog, an issue), report the plan's completion separately from that source's: name the source's items the plan left out, and say whether another plan under .turbo/plans/ covers them.

Rules

• The plan file is read-only during execution. If revisions are needed, run /refine-plan or /draft-plan separately.
• Never skip Step 2.
• Never enumerate or execute the plan's Implementation Steps inline. The work runs through /implement. Restating steps as a turn-level narration counts as inline execution and bypasses the delegation.
• If the plan's Implementation Steps or Verification include git commit, git push, or PR creation, halt before Step 3 and ask the user to remove them via /refine-plan. A Verification item that observes the result of a push without instructing one is not grounds to halt.