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kojiwakayama merged 3 commits into from
Aug 10, 2026
Merged

fix(agent): preserve output after trailing model failure #3533

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d83e58c
fix(agent): preserve output after trailing model failure
kojiwakayama Aug 10, 2026
f7ba44d
fix(agent): keep stream timeouts terminal
kojiwakayama Aug 10, 2026
19aeb29
docs(agent): refresh terminal error references
kojiwakayama Aug 10, 2026
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8 changes: 4 additions & 4 deletions docs/api-reference/veryfront/agent.md
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Original file line number Diff line number Diff line change
Expand Up @@ -802,14 +802,14 @@ Input delivered to a hosted agent-service detached execution callback.
| `getConfirmedProjectContextSwitchId` | Return only the confirmed project id for legacy callers. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/project/context.ts#L258) |
| `getConversationRun` | Return conversation run. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/conversation/durable.ts#L1065) |
| `getConversationRunEventJsonByteLength` | Return conversation run event JSON byte length. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/conversation/run-event-normalization.ts#L27) |
| `getEmptyHostedFinalizedMessageTerminalError` | Error shape for get empty hosted finalized message terminal. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/hosted/stream-terminal-error.ts#L118) |
| `getEmptyHostedFinalizedMessageTerminalError` | Error shape for get empty hosted finalized message terminal. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/hosted/stream-terminal-error.ts#L113) |
| `getForkRuntimeAllowedToolNames` | Return fork runtime allowed tool names. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/runtime/provider-native-tool-inventory.ts#L69) |
| `getForwardedHostedModelId` | Return forwarded hosted model ID. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/hosted/runtime-request-config.ts#L86) |
| `getForwardedHostedRuntimeOverrides` | Return forwarded hosted runtime overrides. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/hosted/runtime-request-config.ts#L96) |
| `getHostedChildWrittenArtifactPath` | Return hosted child written artifact path. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/hosted/child-artifact-support.ts#L112) |
| `getHostedMirroredAbortErrorText` | Return hosted mirrored abort error text. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/streaming/mirrored-tool-chunk-state.ts#L163) |
| `getHostedServiceTokenFromRequest` | Request payload for get hosted service token from. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/service/auth.ts#L201) |
| `getHostedStreamErrorText` | Return hosted stream error text. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/hosted/stream-terminal-error.ts#L113) |
| `getHostedStreamErrorText` | Return hosted stream error text. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/hosted/stream-terminal-error.ts#L108) |
| `getInputRequest` | Request payload for get input. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/input/request-protocol.ts#L254) |
| `getMaxForkRuntimeStepCount` | Return max fork runtime step count. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/streaming/fork-runtime-stream.ts#L445) |
| `getProjectAgentRuntimeAgentIdCandidates` | Return project agent runtime agent ID candidates. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/project/agent-runtime.ts#L223) |
Expand Down Expand Up @@ -988,7 +988,7 @@ Input delivered to a hosted agent-service detached execution callback.
| `selectProviderCompatibleTools` | Select provider compatible tools helper. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/runtime/provider-tool-compat.ts#L126) |
| `shouldBlockHostedChildSameTurnRetry` | Should block hosted child same turn retry helper. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/hosted/child-status.ts#L49) |
| `shouldContinueForkRuntimeStep` | Should continue fork runtime step helper. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/streaming/fork-runtime-step-progress.ts#L42) |
| `shouldFailEmptyHostedFinalizedMessage` | Message shape for should fail empty hosted finalized. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/hosted/stream-terminal-error.ts#L132) |
| `shouldFailEmptyHostedFinalizedMessage` | Message shape for should fail empty hosted finalized. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/hosted/stream-terminal-error.ts#L127) |
| `shouldInjectDefaultResearchArtifactPath` | Should inject default research artifact path helper. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/artifacts/default-research-artifact-policy.ts#L77) |
| `shouldPruneSandboxToolsFromHostedChildRequest` | Request payload for should prune sandbox tools from hosted child. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/hosted/child-requested-tools.ts#L122) |
| `shouldReinforceLoadSkillContinuation` | Should reinforce load skill continuation helper. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/conversation/delegation-policy.ts#L239) |
Expand Down Expand Up @@ -1617,7 +1617,7 @@ Input delivered to a hosted agent-service detached execution callback.
| `HostedServiceProjectAccessError` | Error shape for hosted service project access. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/service/auth.ts#L63) |
| `HostedServiceProjectAccessResult` | Result returned from hosted service project access. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/service/auth.ts#L70) |
| `HostedStreamPartForUiChunkMapping` | Public API contract for hosted stream part for UI chunk mapping. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/chat/hosted-ui-chunk-mapping.ts#L31) |
| `HostedStreamTerminalError` | Error shape for hosted stream terminal. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/hosted/stream-terminal-error.ts#L59) |
| `HostedStreamTerminalError` | Error shape for hosted stream terminal. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/hosted/stream-terminal-error.ts#L54) |
| `HostedTerminalError` | Error shape for hosted terminal. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/hosted/stream-finalization.ts#L6) |
| `HostedUiChunkMappingOptions` | Options accepted by hosted UI chunk mapping. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/chat/hosted-ui-chunk-mapping.ts#L5) |
| `HumanInputField` | Public API contract for human input field. | [source](https://github.com/veryfront/veryfront-code/blob/main/src/agent/input/human-input.ts#L138) |
Expand Down
63 changes: 63 additions & 0 deletions src/agent/hosted/hosted-chat-finalization.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -698,6 +698,69 @@ describe("agent/hosted-chat-finalization", () => {
});
}

it("preserves delivered output when a trailing model step fails after a completed tool handoff", async () => {
const calls: string[] = [];
const terminalStates: HostedLifecycleTerminalState[] = [];

await finalizeHostedChatRun({
kind: "response",
responseMessage: createResponseMessage({ parts: [] }),
isAborted: false,
streamResult: createStreamResult({
text: "The environment panel is open and ready.",
finishReason: "tool-calls",
}),
lifecycleAdapter: createLifecycleAdapter({
calls,
terminalStates,
mirror: createDurableRunMirror({ calls }),
}),
mirroredToolChunkState: createMirroredToolChunkState(),
capturedMessageId: "assistant-message-1",
incompleteToolCallsPartErrorText: "Tool call did not complete",
cleanup: async () => {
calls.push("cleanup");
},
streamError: new Error("Provider request failed with status 502"),
});

assertEquals(terminalStates, [{ status: "completed" }]);
});

it("fails a watchdog timeout after a completed tool handoff", async () => {
const calls: string[] = [];
const terminalStates: HostedLifecycleTerminalState[] = [];

await finalizeHostedChatRun({
kind: "response",
responseMessage: createResponseMessage({ parts: [] }),
isAborted: false,
streamResult: createStreamResult({
text: "The environment panel is open and ready.",
finishReason: "tool-calls",
}),
lifecycleAdapter: createLifecycleAdapter({
calls,
terminalStates,
mirror: createDurableRunMirror({ calls }),
}),
mirroredToolChunkState: createMirroredToolChunkState(),
capturedMessageId: "assistant-message-1",
incompleteToolCallsPartErrorText: "Tool call did not complete",
cleanup: async () => {
calls.push("cleanup");
},
streamError: new Error("Chat stream idle timeout after 300000ms"),
});

assertEquals(terminalStates, [{
status: "failed",
terminalErrorCode: "STREAM_TIMEOUT",
terminalErrorMessage:
"This run timed out after 5 minutes before the agent finished. Try again to continue, or narrow the request.",
}]);
});

it("logs and suppresses cleanup errors after terminal dispatch", async () => {
const calls: string[] = [];
const terminalStates: HostedLifecycleTerminalState[] = [];
Expand Down
7 changes: 2 additions & 5 deletions src/agent/hosted/hosted-chat-finalization.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -9,10 +9,7 @@ import {
toConversationHostedTerminalState,
} from "../conversation/hosted-terminal.ts";
import type { MirroredToolChunkState } from "../streaming/mirrored-tool-chunk-state.ts";
import {
hasCompletedStepSignal,
isLateProviderBodyReadError,
} from "../streaming/stream-outcome.ts";
import { hasCompletedStepSignal, isStreamTimeoutError } from "../streaming/stream-outcome.ts";
import type { HostedChatExecutionLifecycleAdapter } from "./chat-execution-lifecycle-types.ts";
import {
buildDetachedFallbackChunks,
Expand Down Expand Up @@ -246,7 +243,7 @@ function shouldFailStreamError(input: {
if (
input.hasOutput &&
hasFinalStepCompletionSignal(input.finalStep) &&
isLateProviderBodyReadError(input.streamError)
!isStreamTimeoutError(input.streamError)
) {
return false;
}
Expand Down
42 changes: 42 additions & 0 deletions src/agent/hosted/stream-finalization.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -209,6 +209,48 @@ describe("agent/hosted-stream-finalization", () => {
]);
});

it("completes hosted responses after a trailing provider failure", async () => {
const calls: string[] = [];

await finalizeHostedResponse({
isAborted: false,
streamError: new Error("Provider request failed with status 502"),
getFinalStep: async () => ({ step: 1, finishReason: "tool-calls" }),
buildState: async () => ({
persistedMessage: { id: "msg-1" },
finalizedMessage: { id: "msg-1", parts: ["text"] },
fallbackChunks: ["chunk-1"],
hasIncompleteToolParts: false,
metadata: { modelId: "anthropic/claude-haiku-4-5" },
}),
shouldFailEmptyMessage: () => false,
resolveEmptyTerminalError: ({ streamError }) => ({
code: "STREAM_ERROR",
message: streamError instanceof Error ? streamError.message : String(streamError),
}),
appendFallbackChunk: async (chunk) => {
calls.push(`append:${chunk}`);
},
flushMirror: async () => {
calls.push("flush");
},
dispatchTerminalState: async (state) => {
calls.push(`dispatch:${state.status}:${state.metadata?.modelId}`);
},
resolveTerminalState: () => ({ status: "completed" }),
cleanup: async () => {
calls.push("cleanup");
},
});

assertEquals(calls, [
"append:chunk-1",
"flush",
"dispatch:completed:anthropic/claude-haiku-4-5",
"cleanup",
]);
});

it("fails hosted responses with content when a body read fails without a final step finish reason", async () => {
const calls: string[] = [];

Expand Down
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