Skip to main contentTranscript Hygiene (Provider Fixups)
This document describes provider-specific fixes applied to transcripts before a run
(building model context). These are in-memory adjustments used to satisfy strict
provider requirements. They do not rewrite the stored JSONL transcript on disk.
Scope includes:
- Tool call id sanitization
- Tool result pairing repair
- Turn validation / ordering
- Thought signature cleanup
- Image payload sanitization
If you need transcript storage details, see:
Where this runs
All transcript hygiene is centralized in the embedded runner:
- Policy selection:
src/agents/transcript-policy.ts
- Sanitization/repair application:
sanitizeSessionHistory in src/agents/pi-embedded-runner/google.ts
The policy uses provider, modelApi, and modelId to decide what to apply.
Global rule: image sanitization
Image payloads are always sanitized to prevent provider-side rejection due to size
limits (downscale/recompress oversized base64 images).
Implementation:
sanitizeSessionMessagesImages in src/agents/pi-embedded-helpers/images.ts
sanitizeContentBlocksImages in src/agents/tool-images.ts
Provider matrix (current behavior)
OpenAI / OpenAI Codex
- Image sanitization only.
- On model switch into OpenAI Responses/Codex, drop orphaned reasoning signatures (standalone reasoning items without a following content block).
- No tool call id sanitization.
- No tool result pairing repair.
- No turn validation or reordering.
- No synthetic tool results.
- No thought signature stripping.
Google (Generative AI / Gemini CLI / Antigravity)
- Tool call id sanitization: strict alphanumeric.
- Tool result pairing repair and synthetic tool results.
- Turn validation (Gemini-style turn alternation).
- Google turn ordering fixup (prepend a tiny user bootstrap if history starts with assistant).
- Antigravity Claude: normalize thinking signatures; drop unsigned thinking blocks.
Anthropic / Minimax (Anthropic-compatible)
- Tool result pairing repair and synthetic tool results.
- Turn validation (merge consecutive user turns to satisfy strict alternation).
Mistral (including model-id based detection)
- Tool call id sanitization: strict9 (alphanumeric length 9).
OpenRouter Gemini
- Thought signature cleanup: strip non-base64
thought_signature values (keep base64).
Everything else
Historical behavior (pre-2026.1.22)
Before the 2026.1.22 release, Clawdia applied multiple layers of transcript hygiene:
- A transcript-sanitize extension ran on every context build and could:
- Repair tool use/result pairing.
- Sanitize tool call ids (including a non-strict mode that preserved
_/-).
- The runner also performed provider-specific sanitization, which duplicated work.
- Additional mutations occurred outside the provider policy, including:
- Stripping
<final> tags from assistant text before persistence.
- Dropping empty assistant error turns.
- Trimming assistant content after tool calls.
This complexity caused cross-provider regressions (notably openai-responses
call_id|fc_id pairing). The 2026.1.22 cleanup removed the extension, centralized
logic in the runner, and made OpenAI no-touch beyond image sanitization.