diagnose — Root-Cause Isolation & Diagnostic Engine

Isolate root causes of complex bugs, intermittent flakes, and regressions through tight feedback loops, load-bearing minimization, and falsifiable hypotheses before proposing code modifications.

Operating Invariants

• Defect Scope Discipline: Focus exclusively on isolating and resolving the specific reported defect; forbid unsolicited refactoring, styling, or feature alterations outside the defect's blast radius.
• Pre-Mutation Gate: Isolate root causes and present verified findings in Lean Delivery format; forbid modifying codebase implementation files or permanent tests without affirmative human authorization.
• Isolated Scratchpad: Write all temporary reproduction scripts, throwaway harnesses, and fixture traces strictly inside .agents/scratch/; forbid creating temporary test files in repository root or source directories.
• Clean Room Tagging: Tag all temporary diagnostic logging and probes with an isolated unique prefix ([DEBUG-<hex>]); forbid leaving debug probes in working tree upon completion.
• Tight Signal Requirement: Assert the exact user symptom with a single deterministic command executing in seconds; forbid proposing code patches based solely on code inspection.
• Redaction Guardrail: Replace all secrets, tokens, API keys, credentials, and sensitive environment payloads with <REDACTED>; forbid leaking unredacted credentials or sensitive environment payloads in logs, harnesses, or output streams.
• Verification Circuit Breaker: Stop execution immediately upon post-mutation verification failure, report stderr with file citations, and prompt user whether to revert or keep debugging; forbid silent lossy reversions or unguided retry loops.

Domain Engine & Standards

1. Diagnostic Guardrails (When NOT to Touch)