[daewoongoh]

Related GitHub Issue

Closes: #2333

Description

This PR implements automatic background title generation for new root tasks with minimal changes.

Key design points:

• Background Execution: In Task.startTask, title generation starts as a fire-and-forget background operation after
  the first message is saved. It does not block the agent loop or delay startup. Subtasks and resumed history tasks skip
  title generation.
• Resource and Timeout Limits: Title generation uses an isolated singleCompletionHandler with a strict 10-second
  timeout. Prompts longer than 1,000 characters are trimmed before sending to prevent token waste and latency. Generated
  titles are clamped to a maximum of 50 characters.
• Safe Abort on User Cancellation: When a user cancels the task (cancelCurrentRequest, requestAbort, or dispose),
  titleAbortController immediately aborts the underlying network transport. The task title safely falls back to the
  original prompt without overwriting.
• Race and Override Protection: Uses existing store-level locks via renameTaskWithId. If a user manually renames the
  task before generation finishes, the manual title is preserved.
• ReDoS Prevention: Uses a template in src/shared/support-prompt.ts with linear string trimming (indexOf/slice)
  rather than vulnerable regular expressions.
• UI Synchronization: Updates ExtensionStateContext so the generated title immediately reflects in both the chat
  header (TaskHeader) and the recent task list (HistoryPreview).

Test Procedure

1. Run the new and focused unit tests:

npx vitest run core/task/__tests__/taskTitleGenerator.spec.ts core/task/__tests__/Task.titleGeneration.spec.ts
webview-ui/src/context/__tests__/ExtensionStateContext.spec.tsx

2. Verify type checking and linting:

pnpm check-types
pnpm --dir src exec eslint --max-warnings=0 core/task/taskTitleGenerator.ts core/task/Task.ts shared/support-prompt.ts
core/task/__tests__/taskTitleGenerator.spec.ts core/task/__tests__/Task.titleGeneration.spec.ts
pnpm --dir webview-ui exec eslint --max-warnings=0 src/context/ExtensionStateContext.tsx
src/context/__tests__/ExtensionStateContext.spec.tsx

3. Manual verification:
   • Start a new task with a long prompt. Observe that the agent starts immediately and the header updates to a concise
   summary title shortly after.
   • Start a task and click Cancel immediately. Verify that title generation aborts and the prompt remains the title.
   • Check the chat home screen (recent task list) to confirm the title displays properly.

Pre-Submission Checklist

[✓] Issue Linked: This PR is linked to an approved GitHub Issue (see "Related GitHub Issue" above).
[✓] Scope: My changes are focused on the linked issue (one major feature/fix per PR).
[✓] Self-Review: I reviewed my own code with care.
[✓] Writing Style: The PR title and description use Simplified Technical English (ASD-STE100): short sentences, plain words,
active voice, one idea per sentence, no contractions.
[✓] Testing: New and/or updated tests have been added to cover my changes (if applicable).
[✓] Test Helpers (test changes only): Shared test helpers (src/test-utils/, @/utils/test-utils) are used only for mechanical
duplication; test intent and scenario-specific mocks remain visible.
[ ] Visual Snapshot (UI changes only): Not applicable. Existing UI components are reused.
[✓] Documentation Impact: I checked if my changes need documentation updates (see "Documentation Updates" section below).
[✓] Contribution Guidelines: I read and agree to the Contributor Guidelines /CONTRIBUTING.md.

Videos (interaction / animation only)

Documentation Updates

[✓] No documentation updates are required.

Additional Notes

• All 66 added/affected unit tests pass.
• No as any or ESLint suppression count increases.

Get in Touch

hehegwk_2384

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[github-actions]

Review status

Thanks for contributing. This comment tracks the review sequence and the next action.

Current step: Fix the failing required CI checks; awaiting-maintainer requires CI and automated review completion.

Review-state labels are managed by this workflow; do not edit them manually. community-approved is managed the same way — do not add or remove it manually. It signals a fresh community code approval for the current head as an advisory priority only; maintainer review is still required.

[codecov]

Codecov Report

❌ Patch coverage is 94.52055% with 4 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/core/task/Task.ts	94.11%	0 Missing and 2 partials ⚠️
src/core/task/taskTitleGenerator.ts	94.73%	1 Missing and 1 partial ⚠️

📢 Thoughts on this report? Let us know!

[github-actions]

Changed-code mutation testing

Report for PR head da836b466eb0.

Surviving / uncovered mutants	Advisories
48	1

Details: mutants, guidance, and reproduction

Changed-code mutation testing

Package	Changed executable lines	Valid	Killed	Timeout	Survived	No coverage	Result
extension	96	113	68	0	43	2	Advisory findings
webview	3	8	5	0	3	0	Advisory findings

Focused tests

• extension (cwd src): core/task/__tests__/ask-auto-deny.spec.ts, core/webview/__tests__/ClineProvider.spec.ts, api/providers/__tests__/kimi-code.spec.ts, core/webview/__tests__/ClineProvider.taskHistory.spec.ts, core/task-persistence/__tests__/TaskHistoryStore.spec.ts, __tests__/extension.spec.ts, core/task/__tests__/Task.spec.ts, core/task/__tests__/ask-queued-message-drain.spec.ts, core/task/__tests__/Task.persistence.spec.ts, core/tools/__tests__/executeCommand.spec.ts, activate/__tests__/registerCommands.spec.ts, core/webview/__tests__/webviewMessageHandler.spec.ts, core/webview/__tests__/ClineProvider.sticky-mode.spec.ts, core/tools/__tests__/executeCommandTool.spec.ts, core/webview/__tests__/ClineProvider.apiHandlerRebuild.spec.ts, api/providers/fetchers/__tests__/modelCache.spec.ts, core/task/__tests__/Task.streaming-tool-calls.spec.ts, core/webview/__tests__/ClineProvider.sticky-profile.spec.ts, api/providers/__tests__/native-ollama.spec.ts, api/providers/__tests__/lmstudio.spec.ts, core/config/__tests__/importExport.spec.ts, __tests__/ClineProvider.history-resume-delegation.spec.ts, core/context-management/__tests__/context-management.spec.ts, core/task/__tests__/Task.dispose.test.ts, core/config/__tests__/ContextProxy.spec.ts, core/task/__tests__/ask-clear-approval-buttons.spec.ts, api/providers/__tests__/lmstudio-native-tools.spec.ts, api/providers/__tests__/lm-studio.spec.ts, api/providers/__tests__/lite-llm.spec.ts, core/task/__tests__/ask-allowlist-cwd.spec.ts, api/providers/__tests__/opencode-go.spec.ts, core/webview/__tests__/ClineProvider.stale-view.spec.ts, api/providers/__tests__/lm-studio-timeout.spec.ts, core/config/__tests__/ProviderSettingsManager.spec.ts, core/task/__tests__/grace-retry-errors.spec.ts, core/task/__tests__/flushPendingToolResultsToHistory.spec.ts, core/task/__tests__/taskTitleGenerator.spec.ts, __tests__/single-open-invariant.spec.ts, api/providers/__tests__/openrouter.spec.ts, api/providers/fetchers/__tests__/openrouter.spec.ts, core/webview/__tests__/ClineProvider.lockApiConfig.spec.ts, api/providers/__tests__/model-catalog-adapters.spec.ts, core/task/__tests__/Task.throttle.test.ts, core/webview/__tests__/webviewMessageHandler.routerModels.spec.ts, core/assistant-message/__tests__/presentAssistantMessage-custom-tool.spec.ts, core/checkpoints/__tests__/checkpoint.test.ts, core/task/__tests__/Task.run-shadow.spec.ts, core/webview/__tests__/webviewMessageHandler.delete.spec.ts, services/code-index/__tests__/manager.spec.ts, core/assistant-message/__tests__/presentAssistantMessage-tool-usage-attribution.spec.ts, core/task/__tests__/reasoning-preservation.test.ts, __tests__/ClineProvider.delegation.spec.ts, core/webview/__tests__/ClineProvider.flicker-free-cancel.spec.ts, api/providers/__tests__/zoo-gateway.spec.ts, core/task/__tests__/Task.ignored-disabled-tools-notice.spec.ts, api/providers/__tests__/nanogpt.spec.ts, core/condense/__tests__/index.spec.ts, services/code-index/__tests__/code-index-status-manager.spec.ts, api/providers/__tests__/vercel-ai-gateway.spec.ts, activate/__tests__/registerCodeActions.spec.ts, core/webview/__tests__/webviewMessageHandler.checkpoint.spec.ts, core/webview/__tests__/checkpointRestoreHandler.spec.ts, core/task/__tests__/grounding-sources.test.ts, core/webview/__tests__/webviewMessageHandler.edit.spec.ts, utils/__tests__/autoImportSettings.spec.ts, api/providers/__tests__/requesty.spec.ts, api/providers/__tests__/friendli.spec.ts, __tests__/ClineProvider.subtask-links.spec.ts, api/providers/__tests__/io-intelligence.spec.ts, core/webview/__tests__/webviewMessageHandler.openFile.spec.ts, core/webview/__tests__/generateSystemPrompt.spec.ts, core/condense/__tests__/foldedFileContext.spec.ts, api/providers/fetchers/__tests__/lmstudio.test.ts, core/assistant-message/__tests__/presentAssistantMessage-unknown-tool.spec.ts, core/task/__tests__/Task.resume-eviction-race.spec.ts, core/task/__tests__/Task.titleGeneration.spec.ts, extension/__tests__/api-task-conversation-history-length.spec.ts, core/message-manager/index.spec.ts, core/assistant-message/__tests__/presentAssistantMessage-auto-deny.spec.ts, __tests__/removeClineFromStack-delegation.spec.ts, api/providers/__tests__/kenari.spec.ts, core/task/__tests__/Task.abort-reason-race.spec.ts, extension/__tests__/api-start-task-logging.spec.ts, activate/__tests__/handleUri.spec.ts, core/assistant-message/__tests__/presentAssistantMessage-images.spec.ts, core/webview/__tests__/messageEnhancer.test.ts, api/providers/__tests__/poe.spec.ts, core/task/__tests__/apiConversationHistory.spec.ts, core/assistant-message/__tests__/presentAssistantMessage-tool-repetition.spec.ts, core/tools/__tests__/generateImageTool.test.ts, core/condense/__tests__/condense.spec.ts, core/webview/__tests__/webviewMessageHandler.readOriginalContent.spec.ts, core/webview/__tests__/webviewMessageHandler.searchFiles.spec.ts, extension/__tests__/api-configuration.spec.ts, api/__tests__/index.spec.ts, api/providers/fetchers/__tests__/modelEndpointCache.spec.ts, core/webview/__tests__/webviewMessageHandler.cloudAuth.spec.ts, extension/__tests__/api-start-new-task.spec.ts, core/webview/__tests__/webviewMessageHandler.importRooHistory.spec.ts, services/code-index/__tests__/workspace-indexing-enablement-manager.spec.ts, core/webview/__tests__/webviewMessageHandler.readFileContent.spec.ts, core/task/__tests__/Task.pending-action.spec.ts, extension/__tests__/api-has-task-ui-message-text.spec.ts, core/condense/__tests__/rewind-after-condense.spec.ts, __tests__/abandonSubtask.spec.ts, activate/__tests__/handleTask.spec.ts, core/context-management/__tests__/truncation.spec.ts, api/providers/__tests__/unbound.spec.ts, core/task/__tests__/ask-abort-race.spec.ts, utils/__tests__/enhance-prompt.spec.ts, core/webview/__tests__/webviewMessageHandler.abandonSubtask.spec.ts, core/assistant-message/__tests__/presentAssistantMessage.spec.ts, core/webview/__tests__/webviewMessageHandler.lockApiConfig.spec.ts, services/marketplace/__tests__/marketplace-setting-check.spec.ts, extension/__tests__/api-send-message.spec.ts, __tests__/nested-delegation-resume.spec.ts, core/webview/__tests__/ClineProvider.pending-action.spec.ts, extension/__tests__/api-delegation-events.spec.ts, shared/__tests__/support-prompts.spec.ts, core/webview/__tests__/ClineProviderFactory.spec.ts, core/task/__tests__/ToolExecutionContext.spec.ts, services/code-index/__tests__/code-index-scope.spec.ts, extension/__tests__/api-delete-queued-message.spec.ts, __tests__/task-run-dispatch.spec.ts, core/task/__tests__/Task.sticky-profile-race.spec.ts, __tests__/api-subtask.spec.ts, extension/__tests__/api-theme-fixture.spec.ts, test-utils/__tests__/provider.spec.ts, core/task/__tests__/Task.terminal-operation.spec.ts, __tests__/new-task-delegation.spec.ts, core/condense/__tests__/nested-condense.spec.ts, extension/__tests__/api-terminal-profile.spec.ts, core/assistant-message/__tests__/toTelemetryToolName.spec.ts
• webview (cwd .): webview-ui/src/context/__tests__/ExtensionStateContext.spec.tsx

All surviving and uncovered mutants

Warning annotations highlight up to 20 unique locations (maximum 7 per file). This summary lists every advisory mutant.

extension

src/core/task/Task.ts

Line	Status	Mutator	Replacement
3203	Survived	ConditionalExpression	false
3203	Survived	LogicalOperator	this.abort && this.abandoned
3217	Survived	ConditionalExpression	false
3217	Survived	LogicalOperator	(controller.signal.aborted || this.abort) && this.abandoned
3217	Survived	ConditionalExpression	false
3217	Survived	LogicalOperator	controller.signal.aborted && this.abort
3222	Survived	ConditionalExpression	false
3227	NoCoverage	UpdateOperator	i--
3227	Survived	ConditionalExpression	false
3227	Survived	EqualityOperator	i <= 20
3227	Survived	EqualityOperator	i >= 20
3228	Survived	ConditionalExpression	false
3228	Survived	LogicalOperator	(controller.signal.aborted || this.abort) && this.abandoned
3228	Survived	ConditionalExpression	false
3228	Survived	LogicalOperator	controller.signal.aborted && this.abort
3231	Survived	ConditionalExpression	true
3231	Survived	ConditionalExpression	false
3239	Survived	OptionalChaining	existing.title
3243	Survived	ConditionalExpression	false
3243	Survived	LogicalOperator	(controller.signal.aborted || this.abort) && this.abandoned
3243	Survived	ConditionalExpression	false
3243	Survived	LogicalOperator	controller.signal.aborted && this.abort
3249	NoCoverage	StringLiteral	``
3251	Survived	ConditionalExpression	true

src/core/task/taskTitleGenerator.ts

Line	Status	Mutator	Replacement
24	Survived	MethodExpression	cleaned.replace(/^["'`]|["'`]$/g, "")
24	Survived	Regex	/["'`]|["'`]$/g
24	Survived	Regex	/^["'`]|["'`]/g
26	Survived	MethodExpression	cleaned.replace(/[.!?]+$/, "")
26	Survived	Regex	/[.!?]+/
28	Survived	ConditionalExpression	true
28	Survived	EqualityOperator	cleaned.length >= MAX_TITLE_LENGTH
29	Survived	MethodExpression	cleaned.slice(0, MAX_TITLE_LENGTH)
45	Survived	OptionalChaining	prompt.trim
62	Survived	BlockStatement	{}
63	Survived	CallExpression	;
66	Survived	ConditionalExpression	false
67	Survived	StringLiteral	""
67	Survived	ObjectLiteral	{}
67	Survived	BooleanLiteral	false
84	Survived	ConditionalExpression	false
84	Survived	LogicalOperator	controller.signal.aborted && parentSignal?.aborted
92	Survived	StringLiteral	""
95	Survived	CallExpression	;
96	Survived	ConditionalExpression	false
97	Survived	StringLiteral	""

webview

webview-ui/src/context/ExtensionStateContext.tsx

Line	Status	Mutator	Replacement
617	Survived	ConditionalExpression	true
617	Survived	ConditionalExpression	false
617	Survived	EqualityOperator	prevState.currentTaskItem?.id !== item.id

Resolve a mutation gap

Add or strengthen a focused test that fails under the mutation. If the mutant is equivalent, request maintainer approval for the narrowest mutator-specific exclusion and explain why it cannot change behavior:

// Stryker disable next-line ConditionalExpression: normalized input cannot reach the alternate branch
const result = condition ? value : fallback

Broad all exclusions and exclusions without a concrete reason are reported as advisories.

Reproduce locally

From a full checkout containing both commits:

pnpm install --frozen-lockfile
node scripts/stryker-diff.mjs ci --base 73931fe8be253b93ec11103a0672c615e849f895 --head 3668f246525357568be1e745dd37d531d3fd1633

Mutation reports

• extension: reports/mutation/extension/mutation.html
• webview: reports/mutation/webview/mutation.html

The workflow uploads generated reports in the changed-code-mutation-report artifact. A direct artifact link appears below after upload.

Advisory findings

• src/core/task/Task.ts:4501: mutation exclusions must use "// Stryker disable next-line MutatorName: concrete reason"; broad or unreasoned exclusions are not allowed.