Two additive hardening changes on the interleaved-thinking replay path
introduced by this PR's anthropic_content_blocks channel. Both are scoped
to that channel's blast radius; neither changes correct behavior.
1. Replay-time tool-input re-sourcing (credential safety).
The ordered-block channel captures each tool_use `input` from the RAW
API response in normalize_response, which is NOT credential-redacted.
The parallel tool_calls[].function.arguments IS redacted at storage
time (build_assistant_message, #19798). The verbatim-replay fast path
in _convert_assistant_message replayed the raw block input, so a secret
a model inlined into a tool call (e.g. an Authorization header value
passed inside a terminal command) would ride back onto the wire even
though it is redacted everywhere else in history. Re-source tool_use
input from the redacted tool_calls map by
sanitized id; interleave order (the reason this channel exists) is
unaffected. Adapted from #36071, which re-sources tool inputs the same
way on its replay path.
2. Broaden the thinking-replay 400 classifier (defense-in-depth).
error_classifier only matched "signature" + "thinking", so the
frozen-block variant — "thinking ... blocks in the latest assistant
message cannot be modified. These blocks must remain as they were in
the original response." — carried no "signature" token and fell through
to a non-retryable abort. The anthropic_content_blocks channel prevents
the reorder that triggers this 400 at the source, but if any future
mutator reintroduces it, the turn now self-heals via the existing
strip-reasoning-and-retry recovery instead of crash-looping. A negative
case ensures an unrelated "cannot be modified" 400 (no "thinking") is
not swept in. Mirrors the classifier broadening in #36087 and #36071.
Tests
- tests/agent/test_anthropic_thinking_block_order.py: a replay test
asserting an inlined secret is redacted on the wire while interleave
order is preserved.
- tests/agent/test_error_classifier.py: three cases — frozen-block 400
native and via OpenRouter route to thinking_signature/retryable; an
unrelated "cannot be modified" 400 does not.
Both grafts verified RED (tests fail with the change reverted) then GREEN.
Full adapter, transport, classifier and output-field-leak suites pass.
Co-authored-by: AlexanderBFoley <92330381+AlexanderBFoley@users.noreply.github.com>
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