Add accepted-plan decomposition exact-once guards and UI state (#6831)

## Thinking Path

> - Paperclip orchestrates AI agents for zero-human companies, so
planning approvals and child-issue fan-out are part of the core
control-plane loop.
> - Accepted plans are supposed to be a safe bridge from planning into
execution, especially when agents wake from review decisions and reuse
isolated workspaces.
> - The duplicate-subtask incident showed that an accepted plan revision
could be interpreted more than once across overlapping runs, which broke
the single-source-of-truth model for issue decomposition.
> - Fixing that required tightening the backend contract first:
accepted-plan decomposition needs an exact-once fingerprint, durable
claim state, and retry-safe child creation.
> - Once that backend behavior existed, the board still needed
visibility into what happened, so the issue detail view needed a
dedicated decomposition section instead of forcing operators to
reconstruct child creation from raw activity.
> - This pull request adds the exact-once decomposition primitive,
hardens wake routing and regressions around the incident, and surfaces
decomposition state in the UI so future incidents are both prevented and
easier to inspect.

## What Changed

- Added accepted-plan decomposition semantics to
`doc/execution-semantics.md`, including the exact-once fingerprint,
durable claim/result expectations, and retry/resume behavior.
- Added persistent accepted-plan decomposition claims in the backend,
including schema, shared types/validators, service logic, and issue
routes for creating and listing decomposition state.
- Hardened heartbeat routing so an accepted-plan continuation stays
scoped to the relevant planning issue instead of opportunistically
re-decomposing another accepted issue on the same assignee.
- Added regression coverage for the original failure modes: concurrent
same-parent retries, cross-issue accepted-plan isolation, and partial
child recreation under the same fingerprint.
- Added the `Plan decomposition` issue-detail section plus supporting
API/query-key/activity formatting updates so operators can see revision
status, owner, child counts, and the linked child issues directly in the
UI.
- Included the small follow-up UI fix so the decomposition section still
renders when the issue work mode is no longer `planning`.

## Verification

- `pnpm --filter @paperclipai/server typecheck`
- `pnpm --filter @paperclipai/ui typecheck`
- `pnpm --filter @paperclipai/db typecheck`
- `pnpm exec vitest run server/src/__tests__/issues-service.test.ts`
- `pnpm exec vitest run server/src/__tests__/issues-service.test.ts -t
"lists persisted decompositions with child issue summaries"`
- `pnpm exec vitest run server/src/__tests__/issues-service.test.ts -t
"accepted plan decomposition"
server/src/__tests__/heartbeat-accepted-plan-workspace-refresh.test.ts
server/src/__tests__/heartbeat-context-summary.test.ts`
- Manual UI path: create a planning issue without an isolated execution
workspace, add a `plan` document, accept the `request_confirmation`, let
Paperclip create child issues, then reopen the parent issue detail page
and confirm the `Plan decomposition` section shows the accepted
revision, status, idempotent-claim badge, and child links.
- Separate follow-up bug noted during manual UI validation: accepting a
plan on an issue whose run never records `workspace_finalize` is tracked
in `PAPA-445` and is not part of this PR’s fix scope.

## Risks

- This adds a new migration and a large Drizzle snapshot update;
reviewers should confirm the schema shape and generated metadata match
the intended decomposition table.
- The exact-once claim changes sit on the accepted-plan fan-out path, so
regressions there could block legitimate child creation or mis-handle
retries if the claim state machine is wrong.
- The new UI only appears when decomposition records exist; reviewers
should use the manual verification path above rather than expecting
existing issues on a stale local instance to show the section
automatically.
- `PAPA-445` remains an open follow-up for the `workspace_finalize`
accept gate when a planning handoff never records finalize; that bug can
interfere with reproducing the UI flow on isolated workspaces but does
not change the correctness of the exact-once decomposition feature
itself.

> Checked `ROADMAP.md`: this PR is a bug fix / control-plane hardening
change for accepted-plan decomposition, not a new uncoordinated roadmap
feature.

## Model Used

- OpenAI Codex via Paperclip `codex_local` (GPT-5-based coding agent;
exact backend model ID/context window not exposed in the run context),
with repository tool use, shell execution, and code-editing
capabilities.

<img width="806" height="1069" alt="Screenshot 2026-05-27 at 11 05
48 PM"
src="https://github.com/user-attachments/assets/5b00b670-96cd-4470-b0a3-581743bcae28"
/>


## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] If this change affects the UI, I have included before/after
screenshots
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] I will address all Greptile and reviewer comments before
requesting merge

---------

Co-authored-by: Paperclip <noreply@paperclip.ing>

packages/shared/src/index.ts

@@ -473,6 +473,12 @@ export type {
   RequestConfirmationTarget,
   RequestConfirmationPayload,
   RequestConfirmationResult,
+  AcceptedPlanDecompositionStatus,
+  AcceptedPlanDecompositionChild,
+  AcceptedPlanDecomposition,
+  AcceptedPlanDecompositionResult,
+  AcceptedPlanDecompositionChildIssue,
+  AcceptedPlanDecompositionSummary,
   IssueThreadInteractionBase,
   SuggestTasksInteraction,
   AskUserQuestionsInteraction,
@@ -868,6 +874,7 @@ export {
   createIssueSchema,
   createIssueInputSchema,
   createChildIssueSchema,
+  createAcceptedPlanDecompositionSchema,
   resolveCreateIssueStatusDefault,
   createIssueLabelSchema,
   issueBlockedInboxAttentionSchema,
@@ -936,6 +943,7 @@ export {
   releaseIssueTreeHoldSchema,
   type CreateIssue,
   type CreateChildIssue,
+  type CreateAcceptedPlanDecomposition,
   type CreateIssueLabel,
   type UpdateIssue,
   type ResolveIssueRecoveryAction,

packages/shared/src/types/index.ts

@@ -238,6 +238,12 @@ export type {
   RequestConfirmationTarget,
   RequestConfirmationPayload,
   RequestConfirmationResult,
+  AcceptedPlanDecompositionStatus,
+  AcceptedPlanDecompositionChild,
+  AcceptedPlanDecomposition,
+  AcceptedPlanDecompositionResult,
+  AcceptedPlanDecompositionChildIssue,
+  AcceptedPlanDecompositionSummary,
   IssueThreadInteractionBase,
   SuggestTasksInteraction,
   AskUserQuestionsInteraction,

packages/shared/src/types/instance.ts

@@ -29,6 +29,7 @@ export interface InstanceGeneralSettings {
 export interface InstanceExperimentalSettings {
   enableEnvironments: boolean;
   enableIsolatedWorkspaces: boolean;
+  enableIssuePlanDecompositions: boolean;
   enableCloudSync: boolean;
   autoRestartDevServerWhenIdle: boolean;
   enableIssueGraphLivenessAutoRecovery: boolean;

packages/shared/src/types/issue.ts

@@ -129,6 +129,71 @@ export interface LegacyPlanDocument {
   source: "issue_description";
 }
 
+export type AcceptedPlanDecompositionStatus = "in_flight" | "completed";
+
+export interface AcceptedPlanDecompositionChild {
+  projectId?: string | null;
+  projectWorkspaceId?: string | null;
+  goalId?: string | null;
+  blockedByIssueIds?: string[];
+  title: string;
+  description?: string | null;
+  status: IssueStatus;
+  workMode: IssueWorkMode;
+  priority: IssuePriority;
+  assigneeAgentId?: string | null;
+  assigneeUserId?: string | null;
+  requestDepth?: number;
+  billingCode?: string | null;
+  assigneeAdapterOverrides?: IssueAssigneeAdapterOverrides | null;
+  executionPolicy?: IssueExecutionPolicy | null;
+  executionWorkspaceId?: string | null;
+  executionWorkspacePreference?: string | null;
+  executionWorkspaceSettings?: IssueExecutionWorkspaceSettings | null;
+  labelIds?: string[];
+  acceptanceCriteria?: string[];
+  blockParentUntilDone?: boolean;
+}
+
+export interface AcceptedPlanDecomposition {
+  id: string;
+  companyId: string;
+  sourceIssueId: string;
+  acceptedPlanRevisionId: string;
+  acceptedInteractionId: string | null;
+  status: AcceptedPlanDecompositionStatus;
+  requestFingerprint: string;
+  requestedChildCount: number;
+  childIssueIds: string[];
+  ownerAgentId: string | null;
+  ownerUserId: string | null;
+  ownerRunId: string | null;
+  completedAt: Date | string | null;
+  createdAt: Date | string;
+  updatedAt: Date | string;
+}
+
+export interface AcceptedPlanDecompositionResult {
+  decomposition: AcceptedPlanDecomposition;
+  childIssueIds: string[];
+  newlyCreatedChildIssueIds: string[];
+}
+
+export interface AcceptedPlanDecompositionChildIssue {
+  id: string;
+  identifier: string | null;
+  title: string;
+  status: IssueStatus;
+  priority: IssuePriority;
+  assigneeAgentId: string | null;
+  assigneeUserId: string | null;
+}
+
+export interface AcceptedPlanDecompositionSummary extends AcceptedPlanDecomposition {
+  acceptedPlanRevisionNumber: number | null;
+  childIssues: AcceptedPlanDecompositionChildIssue[];
+}
+
 export interface IssueRelationIssueSummary {
   id: string;
   identifier: string | null;

packages/shared/src/validators/index.ts

@@ -186,6 +186,7 @@ export {
   createIssueSchema,
   createIssueInputSchema,
   createChildIssueSchema,
+  createAcceptedPlanDecompositionSchema,
   resolveCreateIssueStatusDefault,
   createIssueLabelSchema,
   issueBlockedInboxAttentionSchema,
@@ -237,6 +238,7 @@ export {
   restoreIssueDocumentRevisionSchema,
   type CreateIssue,
   type CreateChildIssue,
+  type CreateAcceptedPlanDecomposition,
   type CreateIssueLabel,
   type UpdateIssue,
   type IssueExecutionWorkspaceSettings,

packages/shared/src/validators/instance.ts

@@ -38,6 +38,7 @@ export const patchInstanceGeneralSettingsSchema = instanceGeneralSettingsSchema.
 export const instanceExperimentalSettingsSchema = z.object({
   enableEnvironments: z.boolean().default(false),
   enableIsolatedWorkspaces: z.boolean().default(false),
+  enableIssuePlanDecompositions: z.boolean().default(false),
   enableCloudSync: z.boolean().default(false),
   autoRestartDevServerWhenIdle: z.boolean().default(false),
   enableIssueGraphLivenessAutoRecovery: z.boolean().default(false),

packages/shared/src/validators/issue.ts

@@ -412,6 +412,13 @@ export const createChildIssueSchema = withCreateIssueStatusDefault(createIssueBa
 
 export type CreateChildIssue = z.infer<typeof createChildIssueSchema>;
 
+export const createAcceptedPlanDecompositionSchema = z.object({
+  acceptedPlanRevisionId: z.string().uuid(),
+  children: z.array(createChildIssueSchema).min(1).max(25),
+});
+
+export type CreateAcceptedPlanDecomposition = z.infer<typeof createAcceptedPlanDecompositionSchema>;
+
 export const createIssueLabelSchema = z.object({
   name: z.string().trim().min(1).max(48),
   color: z.string().regex(/^#(?:[0-9a-fA-F]{6})$/, "Color must be a 6-digit hex value"),