Why: Some endpoints reject consecutive system messages or a run of the same role. The product already emits several system messages in one request.
Evidence: go test is covered by PrepareMessages tests for merge, strict folding, and tool pairs. Empty MessageShape leaves the transcript unchanged.
Impact: Callers opt in with StreamOptions.MessageShape. Tool calls and tool results are not merged.
Refs: docs/records/2026-10-04-sillytavern-review.md
Why: a crash after a tool was about to run left the call unpaired, and workspace writes could not be rewound.
Evidence: GOWORK=off go test ./runtime/ ./runtime/llm/ ./runtime/checkpoint/ ./runtime/telemetry/ ./runtime/tools/ ./runtime/session/ ./adapters/native/
Impact: pending calls rerun only when both the stored and current replay declarations are safe; otherwise the result is an error. Empty fallback lists and a nil checkpoint log keep the previous behavior.
Refs: feature/durable-rewind
Co-authored-by: Cursor <cursoragent@cursor.com>
Why: Buffering a whole attempt hid live output, overflow detection missed common provider errors, and a cut-off tool call could still run.
Evidence: GOWORK=off go test -race -count=1 ./runtime/llm/ ./runtime/ passed.
Impact: WithRetry forwards events immediately and retries only when nothing has been forwarded. Length or an unclean end drops unfinished tool calls. Loop usage keeps a billing sum and the last request separately.
Refs: feature/llm-robustness
Co-authored-by: Cursor <cursoragent@cursor.com>
Why: the race detector can deliver message_end when the context is already cancelled, because select picks either ready case.
Evidence: GOWORK=off go test -count=50 -race ./runtime/llm/ passed, including TestParseSSECancel.
Impact: a cancelled parse ends with the aborted event.
Refs: D1
Co-authored-by: Cursor <cursoragent@cursor.com>
Why: token budget let the current tool batch run, compaction could split a tool pair or race an append, writes were not crash-atomic, and several MCP and session edges only existed as comments.
Evidence: GOWORK=off go test -count=1 -race ./runtime/ ./runtime/llm/ ./runtime/session/ ./runtime/tools/ ./runtime/mcp/ ./adapters/native/ ./adapters/intentgate/ passed, including the TestR2* cases for budget, replacement, cancel, compaction, SSE, UTF-8, schema, MCP retry, session terminate, poison reload, and registry reload.
Impact: over-budget tool calls are skipped and paired; Stop.Replacement is appended to the session; the intent gate can follow Registry.Reload.
Refs: N5, N6, N7, N8, N9, N11, N12, N15, N16, N17, N18, N19, N21, I9
Co-authored-by: Cursor <cursoragent@cursor.com>
Why: a tool-budget stop left tool calls without results, host callbacks raced, a canceled MCP read stole the next response, and fetch re-resolved after the SSRF check.
Evidence: GOWORK=off go vet ./... && go test -count=1 ./... && go test -race ./runtime/... ./adapters/native/... passed, including TestLoopBudgetToolCallCap, TestParallelHostCallbacksAreSerial, TestStdioSlowCancelThenEcho, TestPresetsAndClientForChatCompletions, TestFetchResolveChangesToLoopbackRejected, and TestFetchHostCheckRedirectStillRejectsPrivate.
Impact: over-budget calls get an error result and no tool event; one Run serializes host callbacks; MCP dispatches by id; anthropic and google presets use OpenAI-compatible chat endpoints; fetch dials the address it just checked. deps/agent-intent is 3130190; error-code-system and logging-system are a3ee67b and 49b5d8b.
Refs: N1, N2, N3, N4, N13, N14
Co-authored-by: Cursor <cursoragent@cursor.com>
Why: A fixed continuation cap and a 4096-token Anthropic fallback stopped long replies before the agent finished.
Evidence: go test ./runtime/ ./runtime/llm/
Impact: MaxLengthContinuations of 0 keeps the old cap of 3; a negative value removes it. Unset Anthropic max_tokens defaults to 128000.
Refs: feature/stream-display-overhaul
Co-authored-by: Cursor <cursoragent@cursor.com>
Why: the direct chat path needs one shared loop for deliverable checks, tool pairing, reminders, and truncated replies, while squad callers keep today's behavior when the new fields stay unset.
Evidence: go test ./... in agent-native passed, including Stop cap, BeforeTool pairing, reminders absent from the session, repeat-guard cap, length continuation, and zero-value loop tests.
Impact: runtime.Config and llm.Event grow optional fields; AgentSession.Prompt copies them through. Squad sessions that leave them zero are unchanged.
Refs: feature/agent-harness-p1
Co-authored-by: Cursor <cursoragent@cursor.com>
Why: The runtime could only speak OpenAI chat completions, so thinking levels, images, and the other vendor wires had nowhere to go.
Evidence: go test -count=1 ./runtime/llm/
Impact: Existing chat-completions calls stay the same unless a thinking level or image is set. Overflow errors are not retried.
Refs: feature/pi-headless N2
Co-authored-by: Cursor <cursoragent@cursor.com>
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