83931a5f3e
`LlmRuntime.adapterStream` normalizes a thrown `LlmError` into the same error `finish` the loop routes to `agent/request-error`, so throwing would reach retry too. The Note claimed otherwise. Yielding is chosen because it reports the attempt's billed usage first and matches the neighbouring `EMPTY_RESPONSE` refusal. The rejection comment repeats the corrected durability wording, and the assembler's delta-only fallback carries a TODO for the empty name it still invents for adapters that never close a tool-call block.
4.1 KiB
Agent Note: Streamed tool-call identity survives empty continuation deltas
Status: implemented
English | 中文
Problem
The DeepSeek SSE translator assigned id and name on every tool-call delta that carried the field, so a continuation delta repeating either as an empty string erased the identity established by the call's first delta. The assembled block reached the loop with an empty name, which the tool registry refuses as unknown tool "". Gateways that fill those fields with null erased the identity the same way, and WireToolCallDelta declared both as string | undefined, keeping the observed null out of the compiler's reach.
The empty identity outlived the turn. appendToolCall and appendToolResult write the block's id verbatim and no write path validates it, while adoptSessionEvent refuses a tool/result whose callId is empty. A session that recorded one such call was writable and no longer loadable: the persistence coordinator wrapped that refusal in SessionPersistenceCorruptionError.
Decision
acceptIdentity accepts only a non-empty string for a tool call's id and name; undefined, null, '', and any non-string leave the established value in place. WireToolCallDelta widens id, function.name, and function.arguments to admit null, so the values gateways actually send are in the type system and the runtime guard is load-bearing rather than speculative.
A tool call still lacking id or name when the stream reaches [DONE] is not closed. The translator reports any pending usage, then ends the response with an error finish carrying the new MALFORMED_TOOL_CALL code, and emits no block-end at all. closeBlock returns which field is missing instead of substituting an empty string, so no path can assemble an unidentified tool call.
MALFORMED_TOOL_CALL joins the default retryable codes described in bounded LLM request recovery; retry reaches the attempt either way, because LlmRuntime.adapterStream normalizes a thrown LlmError into the same error finish the loop routes to agent/request-error. The refusal is yielded rather than thrown so the attempt's already-billed usage still reaches the loop before the failure, and so the refusal follows the same chunk protocol as the EMPTY_RESPONSE case beside it.
Alternatives considered
Concatenate id and name across deltas. Rejected: they are identity, not accumulation. Concatenation produces Globnull against a gateway that sends null, and a doubled name against one that repeats a non-empty value.
Refuse a conflicting non-empty identity mid-stream. Deferred: a gateway that fragments a long tool name would be refused for it, and the [DONE] check already keeps an unusable call away from the loop.
Relax the session reader's empty-callId refusal. Rejected: an empty callId cannot be paired back to the provider on the next request, so accepting it moves the failure into the model request. That refusal is the durable-boundary gate; the producer was the defect.
Refuse as soon as a call's first delta carries no id. Rejected: "first delta only" is a claim about the remote encoder, so a gateway that sends id one delta later would be refused for nothing, and the [DONE] check covers every case an early check would.
Consequences
A continuation delta repeating identity empty or null is inert, so a call keeps the identity its first delta established. A provider that never identifies a call costs a retry instead of an unknown tool "" result and a session that cannot be reopened. Sessions that already recorded an empty callId stay unreadable; recovering them is outside this change.
Testing
translate.spec.ts covers empty and null continuation deltas, a repeated identical identity, parallel calls holding separate identities under empty continuations, and refusal when id or name never arrives — including that usage is reported before the failure and that no block-end precedes it. The two cases that documented lenient empty-identity output now assert refusal. retry-policy.spec.ts pins the new default retryable set.