linear-plan

name	linear-plan
description	Explore the codebase and write a detailed implementation plan into a Linear parent issue's description. Creates sub-issues for each atomic task. Use when an agent has picked up a parent issue and needs to plan the work, or the user says "plan this issue", "/linear-plan".
allowed-tools	["Read","Grep","Glob","Bash(git:*)","Agent"]
argument-hint	<issue-id e.g. ENG-42>

Plan a Linear Issue

Explore the codebase and write the implementation plan for issue $ARGUMENTS.

Context

• Team: Engineering (ENG)
• Project: Landscaper
• Description template: docs/plans/PLAN_TEMPLATE.md — read this first for the exact markdown format
• Workflow doc: docs/LINEAR-WORKFLOW.md

Process

1. Read the issue

Use mcp__linear-server__get_issue with id $ARGUMENTS to get the current description, title, labels, and priority.

2. Explore the codebase

Based on the problem described in the issue:

• Read all files mentioned in the description or context hints
• Use Grep to find related code, error messages, function names
• Use Glob to find relevant test files, types, configs
• Trace the code path from entry point to the bug/gap
• Note exact file paths, line numbers, function names, variable values

3. Write the plan

Using the Parent Issue template from docs/plans/PLAN_TEMPLATE.md, update the issue description with:

Problem — Keep the existing problem statement, refine if your investigation found more detail.

Investigation — Fill in:

• "What exists today" — current implementation with exact file:line references
• "Root cause / gap" — what you found by reading code, not guessing
• "Constraints" — anything that limits the solution (compat, perf, breaking changes)

Plan — Break into phases. Each phase = a logical group of changes. Each step = a specific action with file path and line number.

Acceptance Criteria — Testable outcomes. Last item: "All sub-issues complete".

Context Map — Table of key files, their purpose, and grep hints to load them.

Decisions — Leave empty (filled during implementation).

Use mcp__linear-server__save_issue with id: "$ARGUMENTS" to update the description.

4. Create sub-issues

For each atomic task in the plan:

• Use mcp__linear-server__save_issue to create a sub-issue:
  • title: "[Phase N] Brief action description"
  • team: "Engineering"
  • project: "Landscaper"
  • parentId: $ARGUMENTS
  • state: "Todo"
  • description: Use the Sub-Issue template from docs/plans/PLAN_TEMPLATE.md
  • labels: Same category label as parent
  • priority: Same as parent (or lower for optional tasks)
• Set blockedBy relationships between sequential sub-issues
• Set estimates on each sub-issue

5. Move parent to In Progress and post comment

Use mcp__linear-server__save_issue with id: "$ARGUMENTS", state: "In Progress". Use mcp__linear-server__save_comment on the parent issue: "Plan finalized. Created N sub-issues: [list issue IDs and titles]. Ready for implementation."

6. Report

Tell the user:

• Summary of what you found during investigation
• The plan structure (phases and key tasks)
• Sub-issues created with their IDs
• Any risks or open questions

Rules

• Do NOT create sub-issues until the plan is fully written in the parent description
• Do NOT guess at file paths or line numbers — verify by reading the code
• Do NOT include workflow instructions in the issue description — only the plan content
• Keep sub-issues atomic: one focused change, roughly one PR each
• If the problem is trivial (single file, single change), skip phases — just one sub-issue is fine