Task-state compaction never retries a 504 and reports skipped chunks as not degraded #7718

Summary

Task-state compaction never retries a retryable model error. A gateway 504 on a chunk silently drops that chunk, and the result still reports degraded=false. On a long coding thread, about two thirds of the history reached the checkpoint only as the deterministic ledger.

Problem

Seen 2026-10-12 21:32:53, website thread, mid-turn compression (prompt_tokens=351287 trigger=350000):

• dispatching task-state compaction … messages=542 chunks=3 approx_input_tokens=277155.
• Chunk 1 at 21:33:55 and chunk 2 at 21:34:59 each got managed invoke failed: status=Some(504) … retryable=true after ~62 s, then keeping the previous state for this chunk.
• 21:35:56: task-state compaction complete … chunks_skipped=2 degraded=false.

Root cause (tinyagents crates/tinyagents-harness/src/summarization/task_state/mod.rs):

• :263-266 self.model.invoke(...).await.map_err(...)?. Any invoke error leaves on the first try. The STATE_ATTEMPTS = 2 loop (:47) only retries markup/JSON parse failures.
• :344-349: the error is swallowed as "keeping the previous state".
• :353: degraded = state.is_none(), so skipped chunks are invisible.

OpenHuman sets chunk size (window*2/5).clamp(4_000, 100_000) (agent/tinyagents/harness_context_ladder.rs:280-282). A ~92k-token chunk ran ≥60 s through the managed gateway, which answered 504. The ~60 s limit is inferred from the timings.

Introduced by tinyagents PR #282 / openhuman #6963 (2026-10-03).

Solution (optional)

• Owner tinyhumansai/tinyagents: retry retryable transport errors (5xx/timeout) inside the attempt loop, and report partial degradation (degraded = skipped > 0 or a partial flag).
• OpenHuman: lower the managed-route chunk cap (e.g. 40–50k) so one call fits under the gateway timeout.

Acceptance criteria

• Repro gone — a 504 on a chunk is retried, and a skipped chunk is reported as degraded.
• Regression safety — a harness test with a model returning a retryable error once.
• Diff coverage ≥ 80%

Related

#6963.