implement-plan

name	implement-plan
description	Implements approved technical plans from thoughts/shared/plans with phased execution and verification. Use when asked to implement or carry out a plan file.
argument-hint	[plan-file-path] [linear-issue-key (optional)]

Implement Plan

Implements an approved technical plan from thoughts/shared/plans/ with phased execution and verification.

Getting Started

• If a plan path is provided as $ARGUMENTS, read the plan completely and check for any existing checkmarks (- [x]).
• If a Linear issue key is provided (e.g. ENG-1241), resolve it via mcp__linear-server__get_issue and use it for progress updates throughout execution.
• Read the original ticket and all files mentioned in the plan.
• Read files fully (no limit/offset); ensure complete context.
• Think through how the pieces fit together before making changes.
• Create a todo list to track progress.
• Start implementing once the scope is clear.
• If no plan path is provided, ask for one.

Implementation Philosophy

• Follow the plan's intent while adapting to what you find.
• Implement each phase fully before moving to the next.
• Verify changes make sense in the broader codebase context.
• Update checkboxes in the plan as sections are completed.

If you encounter a mismatch between plan and codebase:

Issue in Phase [N]:
Expected: [what the plan says]
Found: [actual situation]
Why this matters: [explanation]

How should I proceed?

Verification Approach

After implementing a phase:

• Run the success criteria checks (usually make check test covers everything).
• Fix any issues before proceeding.
• Update progress in both the plan and your todos.
• Check off completed items in the plan file itself.
• Pause for human verification after automated checks unless explicitly instructed to execute multiple phases.

Manual verification pause format:

Phase [N] Complete - Ready for Manual Verification

Automated verification passed:
- [List automated checks that passed]

Please perform the manual verification steps listed in the plan:
- [List manual verification items from the plan]

Let me know when manual testing is complete so I can proceed to Phase [N+1].

Do not check off manual testing items until the user confirms completion.

Linear Progress Updates (when issue key provided)

When a Linear issue key is provided, keep the issue synced as work progresses:

• After automated checks pass for a phase:
  • Update the Linear issue description to check off the corresponding checkboxes (e.g. - [ ] → - [x]) using mcp__linear-server__update_issue with the updated description markdown.
  • Post a concise progress comment via mcp__linear-server__create_comment summarizing completed scope, acceptance commands run, and results.
  • Move the issue to in-review status via mcp__linear-server__update_issue.
    • If the correct status name is unclear, query via mcp__linear-server__list_issue_statuses and ask before changing state.
• After manual verification is confirmed: update the description to check off manual verification checkboxes and post a confirming comment.

Rules:

• Always read the current issue description before updating it to avoid overwriting other changes.
• Only check off items in the description that have actually been verified to pass.
• Do not change issue status before automated checks pass.

If You Get Stuck

• Re-read all relevant code before making assumptions.
• Consider whether the codebase evolved since the plan was written.
• Present the mismatch clearly and ask for guidance.
• Spawn sub-agents via the Task tool for targeted investigation:
  • codebase-analyzer — trace how a specific component works when you need deeper understanding
  • codebase-pattern-finder — find existing patterns to follow when implementing something unfamiliar
  • web-search-researcher — research external APIs, unfamiliar errors, or version-specific docs
• Keep sub-agent usage focused; provide specific questions and file paths when spawning them.

Resuming Work

• If the plan has existing checkmarks, trust completed work and start from the first unchecked item.
• Verify previous work only if something seems off.
• Maintain forward momentum toward the end goal.