Introduces the building blocks for the thinking-signature pool feature
without activating any runtime behavior. Nothing uses these new types
yet — Phase 3 will wire them into the retry loops.
New package internal/service/signature adds:
- SignaturePool interface + Bucket helpers (oauth shared / apikey per-account)
- ReplaceThinkingSignaturesInBody / ReplaceThinkingSignaturesInClaudeRequest
pure functions that cycle through pool entries for M>N replacements
- Harvester io.ReadCloser decorator for SSE + non-streaming JSON that
extracts content_block.signature fields best-effort into the pool
- 1h soft TTL constant for lazy expiry
New repository adapter internal/repository/signature_pool_cache.go
implements Redis ZSET storage with a single Lua script handling atomic
add + lazy expiry cleanup + capacity trim. Registered via
ProvideSignaturePool in the wire ProviderSet.
Settings extension: RectifierSettings gains a SignaturePoolSize int
field (0 = pool disabled / sticks with strip behavior; >0 = pool replace
is active). Threaded through service view, DTO, and handler GET/PUT
paths with bounds validation (max 1000).
ctxkey.IsSignatureRectifyRetry added so the harvester can later skip
ingesting signatures from retry requests we ourselves injected.
erio
2df77c1604