Investigate GitHub Issue

Investigate the following GitHub issue: $ARGUMENTS

Instructions

Phase 1: Fetch Issue Details

1. Parse the input:
   • DX-123 or linear.app URL → Linear ticket
   • #123, bare number, or github.com URL → GitHub issue
2. Fetch the ticket:
   • GitHub: gh issue view <number> --json title,body,labels,comments,author,createdAt,state
   • Linear: bash .agents/skills/triage/scripts/linear-fetch.sh issue DX-123
3. Extract: error messages, stack traces, reproduction steps, environment details

Phase 2: Identify Affected Package(s)

1. Check issue labels for pkg:* tags
2. Search title/body for package names or import statements
3. Check stack traces for file paths
4. Package folders are in packages/ — use labels and keywords to identify

Phase 3: Deep Analysis

1. Search for error messages and referenced functions in the codebase
2. Trace the execution path from entry point to the reported behavior
3. Check recent commits: git log --oneline -20 -- packages/<name>
4. Search similar issues: gh issue list --search "<keywords>" --state all --limit 10

Phase 4: Root Cause Analysis

Determine category: bug in logic, API change, type mismatch, missing validation, race condition, environment issue, configuration, or documentation gap.

Phase 5: Propose Solutions

For each root cause: the fix (file paths + line numbers), test coverage needed, verification commands.

Output

1. Extract identifier from arguments (issue 424 → 424, ticket DX-296 → DX-296, text → slugified)
2. mkdir -p claude-output
3. Write to claude-output/investigate-<identifier>.md
4. Confirm to user: "Investigation written to claude-output/investigate-<identifier>.md"

Output Structure

# Investigation: Issue #<number>

**Title:** | **URL:** | **Created:** | **State:** | **Author:**

## Summary

## Affected Package(s) (table: Package, Confidence, Evidence)

## Issue Details (Reported Behavior, Expected Behavior, Environment, Reproduction Steps)

## Code Analysis (Relevant Files table, Execution Flow, Code snippets)

## Root Cause (Category, Explanation, Evidence)

## Proposed Solutions (Changes table, Code before/after, Tests to add, Verification)

## Similar Issues

## Notes / Risks

## Next Steps