Diagnosing

Strike 1 of the unstuck protocol. Systematic root cause investigation.

Pre-Check: Knowledge Pack

If a knowledge pack was loaded by the orchestrator:

1. Scan the "Common Errors" table — does the error match a known pattern?
2. If match found: follow the "Check" column directly before generic investigation
3. Run relevant "Diagnostic Commands" from the knowledge pack
4. Check "Gotchas" for framework-specific traps

If a match resolves the issue, report resolved and skip remaining steps.

Step 1: Read the Error Completely

• Read the FULL stack trace, not just the last line
• Note the originating file and line number
• Identify the error type/code (e.g., TypeError, HTTP 422, exit code 1)
• Check if the error message contains a suggestion or hint

Record:
- Error type: {TYPE}
- Error message: {MESSAGE}
- Origin: {FILE}:{LINE}
- Error code: {CODE} (if any)

Step 2: Reproduce Consistently

• Identify the exact command or action that triggers the error
• Run it once to confirm it still fails
• Note if it fails consistently or intermittently

If intermittent: gather 3 runs, note which succeed/fail and any differences.

Step 3: Check Recent Changes

git diff HEAD~3 --stat
git log --oneline -5

• Did a recent change touch the failing file or its dependencies?
• Were config files, dependencies, or environment changed recently?
• Was a library updated that could cause breaking changes?

Step 4: Gather Evidence at Boundaries

Trace the data flow backward from the error:

1. Read the failing function/method
2. Check the inputs to that function — are they what you expect?
3. Check the caller — is it passing correct arguments?
4. Check configuration/environment values used in the flow

At each boundary, verify: "Is the data correct here?"

Find the boundary where data goes from correct → incorrect. That boundary contains the bug.

Step 5: Form a Single Hypothesis

Based on evidence gathered:

Hypothesis: "{X} is the cause because {Y}"
Evidence supporting: {LIST}
Evidence against: {LIST}

The hypothesis must be specific and testable — not "something is wrong with auth" but "the JWT token is missing the sub claim because the user ID is None at token creation."

Step 6: Test Minimally

• Make the smallest possible change to test the hypothesis
• Change ONE variable at a time
• If the fix works: verify it doesn't break anything else
• If the fix doesn't work: the hypothesis was wrong — record what was learned

Outcome

Report to the orchestrator:

Diagnosis:
  Hypothesis: {HYPOTHESIS}
  Change made: {DESCRIPTION}
  Result: { resolved | not resolved }
  Evidence: {WHAT_WAS_LEARNED}

If resolved, include what fixed it and why. If not resolved, include why the hypothesis was wrong and what was ruled out.