Root Cause Trace

Trace the root cause of a TypeScript error. Don't just fix the symptom — find what changed upstream.

Steps

1. Parse the user's input:

• If file:line format: use both
• If just a file: let the tool find the first error
• If no input: check files edited in the current conversation for errors

1. Run root_cause_trace with the file path and optional line

1. Present the result:

• The error: what diagnostic, where
• The root cause: which declaration changed and why it caused this
• Evidence chain: definition → change → impact
• Suggested fix: if the tool provides one
• Other candidates: if the top result has low confidence

1. If confidence is low, suggest:

• Running /check on related files to find more errors
• Running /impact on the suspected symbol to see full blast radius

1. If the user wants to fix it, use gather_context on the root cause file to get the relevant code