Replace isExtendedThinkingModel() model-name check with hasSignedThinkingBlocksInHistory()
which scans message history for real Anthropic-signed thinking blocks.
Content-based gating is more robust than model-name checks — works correctly
with custom model IDs, proxied models, and new model releases without code changes.
- Add isSignedThinkingPart() that matches type thinking/redacted_thinking with valid signature
- Skip synthetic parts (injected by previous hook runs)
- GPT reasoning blocks (type=reasoning, no signature) correctly excluded
- Add comprehensive tests: signed injection, redacted_thinking, reasoning negative case, synthetic skip
Inspired by PR #2653 content-based approach, combined with redacted_thinking support from 0732cb85.
Ultraworked with Sisyphus
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
YeonGyu-Kim