kandev/docs/plans/continuous-conversation-history-pagination/task-01-establish-transcript-start.md

id, title, status, wave, depends_on, plan, requirements, acceptance_criteria, system_design

id	title	status	wave	depends_on	plan	requirements	acceptance_criteria	system_design
01-establish-transcript-start	Establish the true transcript start	done	1		plan.md	REQ-UI-TASK-PROMPT-TRANSCRIPT-VISIBILITY-001	AC-UI-TASK-PROMPT-TRANSCRIPT-VISIBILITY-001.1 AC-UI-TASK-PROMPT-TRANSCRIPT-VISIBILITY-001.2 AC-UI-TASK-PROMPT-TRANSCRIPT-VISIBILITY-001.3 AC-UI-TASK-PROMPT-TRANSCRIPT-VISIBILITY-001.4 AC-UI-TASK-PROMPT-TRANSCRIPT-VISIBILITY-001.10	../../specs/ui/system-design/task-prompt-transcript-visibility.md

Task 01: Establish the true transcript start

Summary

Record when session message history has authoritative pagination metadata and use that state to prevent a bounded tool-only window from synthesizing the task description. Preserve bounded opening and prompt-#1 behavior.

In scope

• Add and maintain per-session message-history initialization state.
• Expose initialized and raw-history state through the session hook.
• Gate task-description fallback on initialized, exhausted history.
• Preserve stored user prompts as authoritative.
• Add the failing tool-only-window regression before implementation.

Out of scope

• Sentinel continuation and retry-control behavior.
• Backend message APIs or persistence.
• Eager history loading.

Acceptance

• An initialized window with older history and no user row renders no synthetic task description.
• Exhausted legacy history with no user row renders one non-empty fallback.
• Uninitialized, refetching, prompt-#1, and empty-description cases do not produce a misleading or duplicate fallback.

Verification

cd apps/web
pnpm exec vitest run \
  hooks/use-processed-messages-fallback.test.ts \
  hooks/domains/session/use-session-messages.test.ts \
  hooks/domains/session/use-session-message-fetch.test.ts \
  lib/state/slices/session/session-slice.merge-messages.test.ts \
  components/task/chat/message-list-shared.test.tsx
pnpm run typecheck

Files likely touched

• apps/web/lib/state/slices/session/types.ts
• apps/web/lib/state/slices/session/session-slice.ts
• apps/web/lib/state/slices/session/session-slice.merge-messages.test.ts
• apps/web/lib/state/hydration/merge-strategies.ts
• apps/web/hooks/domains/session/use-session-messages.ts
• apps/web/hooks/domains/session/use-session-message-fetch.test.ts
• apps/web/components/task/chat/use-chat-panel-state.ts
• apps/web/hooks/use-processed-messages.ts
• apps/web/hooks/use-processed-messages-fallback.test.ts
• apps/web/components/task/chat/message-list-shared.test.tsx

Dependencies

None.

Risks

• Boot-hydrated and client-fetched sessions must set the same initialization state.
• Live rows arriving before the newest snapshot must not claim that history is initialized or exhausted.
• Purged sessions must not retain metadata that affects a later session.

Parallelism

sequential

Inputs

• REQ-UI-TASK-PROMPT-TRANSCRIPT-VISIBILITY-001 acceptance criteria .1 to .4 and .10.
• History state and opening boundary sections of the system design.
• Existing message-window reconciliation and processed-message fallback tests.

Results

• Added per-session historyInitialized metadata with safe defaults, live-row isolation, newest-window fetch/boot hydration, and purge-compatible state.
• Gated the task-description fallback on initialized, exhausted history while preserving stored user prompts and the prompt-#1 visible boundary.
• Added regressions for older history, uninitialized history, live inserts, and authoritative fetch metadata.
• The focused Task 01 Vitest suite passed (5 files, 87 tests).
• pnpm run typecheck passed.