kandev/docs/plans/initial-task-brief/task-02-first-message-composition.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
02-first-message-composition	First-message composition	done	2	01-atomic-admission	plan.md	REQ-TASKS-INITIAL-TASK-BRIEF-001	AC-TASKS-INITIAL-TASK-BRIEF-001.1 AC-TASKS-INITIAL-TASK-BRIEF-001.2 AC-TASKS-INITIAL-TASK-BRIEF-001.4 AC-TASKS-INITIAL-TASK-BRIEF-001.5 AC-TASKS-INITIAL-TASK-BRIEF-001.8 AC-TASKS-INITIAL-TASK-BRIEF-001.9 AC-TASKS-INITIAL-TASK-BRIEF-001.10	../../specs/tasks/system-design/initial-task-brief.md

Task 02: First-message composition

Summary

Compose the original brief with the additional instruction before first-message persistence. Dispatch the selected stored content and its matching trusted expansion.

In scope

• Opt eligible ordinary CREATED direct messages into Task 01 admission.
• Capture and validate the task description after task/session authorization.
• Keep exact equality, empty descriptions, passthrough, saved prompts, references, and attachments correct.
• Preserve visible direct content through workflow composition and session redirection.
• Exclude Office, ephemeral Quick Chat, configuration, and already-prompted sessions.

Out of scope

Do not change unrelated launch policy, historical messages, or public API fields.

Acceptance

• TestWSAddMessage_InitialTaskBrief fails on the original branch and then proves saved and captured content contain both texts once.
• TestStartCreatedSession_InitialTaskBrief proves real launch composition preserves both texts with empty, placeholder, and replacing step templates.
• Retry, queued promotion, plan comments, and excluded modes pass their regression cases without a second dispatch.

Verification

Start with failing behavior assertions before implementation. Then run this block from the repository root:

(cd apps/backend && go test -tags fts5 ./internal/task/handlers ./internal/task/service ./internal/orchestrator -run 'InitialTaskBrief|WSAddMessage|StartCreatedSession|InitialPromptFallback' -count=1)
git diff --check

Files likely touched

• apps/backend/internal/task/handlers/message_handlers.go
• apps/backend/internal/task/handlers/message_handlers_initial_task_brief.go (new helper)
• apps/backend/internal/task/handlers/message_handlers_initial_task_brief_test.go (new)
• apps/backend/internal/task/service/service_messages.go
• apps/backend/internal/orchestrator/task_operations.go
• apps/backend/internal/orchestrator/task_operations_initial_task_brief_test.go (new)

Dependencies

Task 01 must be complete.

Risks

Never trust a browser initial-content flag or client-supplied system block. Do not let a second workflow transform replace already composed direct content. Preserve the original request fingerprint across candidate preparation.

Parallelism

sequential

Inputs

• Requirements.
• System design.
• Package evidence and test matrix.

Results

• Composed the raw trimmed task description and first direct instruction before saved-prompt expansion, so both inputs share one acceptance-time snapshot.
• Preserved the selected stored content and its matching trusted prompt context through created-session dispatch and workflow prompt composition, including an explicit accepted-empty expansion state.
• Kept equality, empty descriptions, attachments, saved references, plan comments, queued promotion, session redirection, and excluded modes on their existing paths.
• Added task/session pair authorization before mutable task reads and a stale-description retry that rebuilds only the candidate without repeating turn-start or title hooks.
• Added handler regressions for distinct saved references, brief-only references, identical brief and instruction deduplication, definitions changed after admission, queued delivery, mismatched task/session IDs, stale descriptions, and concurrent first sends.
• Restricted created-session launch to the atomically selected candidate; later contenders use an admission-order queue marker and the queue fast path defers until the selected launch completes.
• Added handler and orchestrator regressions for empty, placeholder, and replacing workflow step prompts.
• Focused handler, service, and orchestrator tests passed, including TestWSAddMessage_InitialTaskBriefExpandsCombinedPromptAtAdmission, TestWSAddMessage_InitialTaskBriefKeepsAcceptedExpansionWhenDefinitionsChange, TestWSAddMessage_QueuedInitialTaskBriefPersistsAcceptedExpansion, TestWSAddMessage_RejectsMismatchedTaskSessionBeforeReadingTask, TestWSAddMessage_ConcurrentInitialBriefStartsOnlyAdmittedCandidate, TestWSAddMessage_RefreshesStaleBriefWithoutRepeatingTurnStart, TestStartCreatedSession_InitialTaskBrief, and TestApplyWorkflowAndPlanMode_PreservesEmptyAcceptedPromptSnapshot.