# Scratchpad — Workflow Step Quota Accounting

- Plan slug: `2026-04-28-workflow-step-quota-accounting`
- Created: `2026-04-28`

## What This Is

Rolling notes for the workflow step quota accounting plan. Keep decisions, discoveries, commands, links, and gotchas here as implementation proceeds.

## Decisions

- (2026-04-28) Count every workflow step attempt at step start. Retries, failed attempts, `forEach` item attempts, and wait/human-task entry attempts all count. Quota-blocked steps do not count because they never start.
- (2026-04-28) Quota exhaustion pauses workflow runs instead of failing them. Runs remain at the current `node_path` with `workflow_runs.status = 'WAITING'` and a `workflow_run_waits.wait_type = 'quota'` record.
- (2026-04-28) Use Stripe subscription periods as the primary payment period source: `stripe_subscriptions.current_period_start` through `current_period_end`.
- (2026-04-28) Do not use contract `recurring_service_periods`, cadence ownership, invoice windows, or contract-line periods for this feature. Workflow quota is tenant platform licensing usage, not client contract billing usage.
- (2026-04-28) If no valid active Stripe period exists, fall back to the current UTC calendar month with tier defaults.
- (2026-04-28) Tier defaults are `solo = 150`, `pro = 750`, and `premium = 10000` workflow step attempts per period.
- (2026-04-28) Use hybrid limit resolution: Stripe price metadata first, Stripe product metadata second, tier default last.
- (2026-04-28) Support `workflow_step_limit=unlimited`; unlimited tenants still record usage but are not quota-paused.
- (2026-04-28) Use a dedicated atomic counter table for enforcement and keep `workflow_run_steps` as the detailed audit/reconciliation ledger.
- (2026-04-28) Use column name `tenant` in new schema rather than `tenant_id`, per project schema convention and user instruction.
- (2026-04-28) Resume quota-paused workflows through both a recurring job and a manual resume action. Manual resume must not bypass quota.

## Discoveries / Constraints

- (2026-04-28) DB workflow runtime creates step rows in `shared/workflow/runtime/runtime/workflowRuntimeV2.ts` inside `executeRun()` after `resolveStepAtPath()` and before `executeStep()`.
- (2026-04-28) Temporal runtime creates projected step rows in `ee/temporal-workflows/src/activities/workflow-runtime-v2-activities.ts` via `projectWorkflowRuntimeV2StepStart()`.
- (2026-04-28) Existing workflow runtime tables include `workflow_runs`, `workflow_run_steps`, `workflow_run_waits`, `workflow_action_invocations`, `workflow_run_snapshots`, and `workflow_runtime_events` from migration `server/migrations/20251221090000_create_workflow_runtime_v2_tables.cjs`.
- (2026-04-28) Tenant tiers are defined in `packages/types/src/constants/tenantTiers.ts` as `solo`, `pro`, and `premium`.
- (2026-04-28) `packages/types/src/constants/tierFeatures.ts` already notes that `WORKFLOW_DESIGNER` is available to all tiers and that a usage cap was planned separately.
- (2026-04-28) Stripe subscription table is created in EE migration `ee/server/migrations/20251014120000_create_stripe_integration_tables.cjs` and includes `current_period_start`, `current_period_end`, `stripe_price_id`, `status`, and `metadata`.
- (2026-04-28) Existing scheduled job infrastructure includes `server/src/lib/jobs/initializeScheduledJobs.ts`, `registerAllHandlers.ts`, and `jobHandlerRegistry.ts`.

## Commands / Runbooks

- (2026-04-28) Create plan folder: `mkdir -p ee/docs/plans/2026-04-28-workflow-step-quota-accounting`.
- (2026-04-28) Validate plan JSON manually or with the alga-plan validation helper after edits.

## Links / References

- `shared/workflow/runtime/runtime/workflowRuntimeV2.ts`
- `ee/temporal-workflows/src/activities/workflow-runtime-v2-activities.ts`
- `server/migrations/20251221090000_create_workflow_runtime_v2_tables.cjs`
- `ee/server/migrations/20251014120000_create_stripe_integration_tables.cjs`
- `packages/types/src/constants/tenantTiers.ts`
- `packages/types/src/constants/tierFeatures.ts`
- `server/src/lib/jobs/initializeScheduledJobs.ts`
- `server/src/lib/jobs/registerAllHandlers.ts`
- `server/src/lib/jobs/jobHandlerRegistry.ts`

## Open Questions

- Should zero-limit metadata ever be valid, or should it remain invalid and fall back to tier default? Current PRD treats zero as invalid.
- What exact permission should gate manual quota resume if no dedicated workflow-run operation permission exists?
- Should rollout include an explicit enforcement feature flag, or is the plan to enforce immediately once shipped?

## Implementation Notes (2026-04-28)

- Added shared quota service at `shared/workflow/runtime/services/workflowStepQuotaService.ts`.
- Resolver behavior implemented:
  - Preferred Stripe subscription period from `stripe_subscriptions` with status priority `trialing > active > past_due > unpaid` and valid `current_period_start/end`.
  - Fallback period to UTC month boundaries when Stripe tables/subscription period are unavailable.
  - Tier defaults from `tenants.plan`: `solo=150`, `pro=750`, `premium=10000`.
  - Metadata precedence implemented: `stripe_prices.metadata.workflow_step_limit` -> `stripe_products.metadata.workflow_step_limit` -> tier default.
  - `workflow_step_limit=unlimited` maps to `effective_limit = null`.
  - Invalid metadata safely ignored (falls through to next source).
- Atomic reservation implemented in same service:
  - Upserts `workflow_step_usage_periods` by `(tenant, period_start, period_end)`.
  - Takes row lock (`FOR UPDATE`) before reservation decision.
  - Finite limits reject at/above limit without increment.
  - Unlimited limits always increment `used_count`.
- DB runtime enforcement integrated in `shared/workflow/runtime/runtime/workflowRuntimeV2.ts`:
  - Reservation now occurs before STARTED step row creation.
  - On exhaustion: run is set `WAITING`, `node_path` preserved, and quota wait (`wait_type='quota'`) is created/reused.
- Temporal projection enforcement integrated in `ee/temporal-workflows/src/activities/workflow-runtime-v2-activities.ts` and workflow handling in `ee/temporal-workflows/src/workflows/workflow-runtime-v2-run-workflow.ts`:
  - Reservation happens before STARTED step projection.
  - On exhaustion: quota wait created/reused, run marked WAITING, activity returns `quotaPaused` result, workflow exits without treating it as failure.
- Added integration tests in `server/src/test/integration/workflowStepQuotaService.integration.test.ts` covering:
  - Stripe period resolution.
  - Fallback calendar month + tier default.
  - Metadata precedence and unlimited.
  - Finite reservation rejection-at-limit.
  - Unlimited reservation increments.
- Command run:
  - `cd server && npm test -- src/test/integration/workflowStepQuotaService.integration.test.ts` (pass).
- Added T005 coverage in `server/src/test/integration/workflowStepQuotaService.integration.test.ts` to verify uniqueness and upsert behavior on `(tenant, period_start, period_end)`.
- Added structured observability logs in `shared/workflow/runtime/services/workflowStepQuotaService.ts`:
  - `logger.debug` on successful quota reservation with tenant/period/limit context.
  - `logger.warn` on quota exhaustion at reservation with tenant/period/used/limit context.
  - `logger.warn` when invalid `workflow_step_limit` metadata is detected on Stripe price/product and fallback resolution is used.
  - `logger.info` when resolver uses fallback UTC calendar periods due to missing Stripe period or missing Stripe tables.
- Validation command run:
  - `cd server && npm test -- src/test/integration/workflowStepQuotaService.integration.test.ts` (pass).
- Added scheduled quota resume scan job handler: `server/src/lib/jobs/handlers/workflowQuotaResumeScanHandler.ts`.
  - Scans `workflow_run_waits` with `wait_type='quota'` and `status='WAITING'`.
  - Uses `FOR UPDATE SKIP LOCKED` + configurable `batchSize` (default 100) for concurrency-safe scan batches.
  - Applies per-tenant capacity gating from `workflowStepQuotaService.resolveQuotaSummary()`:
    - finite tenants resume up to `effectiveLimit - usedCount`
    - unlimited tenants resume all selected waits
  - Resolves selected waits, sets runs to `RUNNING`, writes run log entries, and re-enters DB runtime via `WorkflowRuntimeV2.executeRun()` without pre-consuming quota.
- Registered/scheduled job plumbing:
  - `server/src/lib/jobs/registerAllHandlers.ts` registration name `workflow-quota-resume-scan`.
  - `server/src/lib/jobs/index.ts` legacy registration + `scheduleWorkflowQuotaResumeScanJob()`.
  - `server/src/lib/jobs/initializeScheduledJobs.ts` schedules recurring scan cron `*/5 * * * *`.
- Added manual quota resume action:
  - `ee/packages/workflows/src/actions/workflow-runtime-v2-actions.ts` exports `resumeWorkflowRunFromQuotaPauseAction`.
  - Verifies permission and tenant ownership, requires `WAITING` + `quota` wait, checks current quota summary, returns structured exhausted-quota response when still blocked, otherwise resolves quota wait and executes runtime (no bypass of step-start reservation).
- Validation attempt:
  - `cd server && npm test -- src/test/integration/workflowRuntimeV2.control.integration.test.ts` (fails in current env due missing module resolution for `@alga-psa/authorization/kernel`, unrelated to quota changes).
- Added test coverage for concurrent finite quota reservations:
  - `server/src/test/integration/workflowStepQuotaService.integration.test.ts`
  - New case fires 12 concurrent reservations against finite limit 3 and asserts exactly 3 allows, 9 denies, and persisted `used_count=3`.
- Validation command run:
  - `cd server && npm test -- src/test/integration/workflowStepQuotaService.integration.test.ts` (pass).
- Added minimal run-level quota pause surfacing in workflow run detail responses:
  - `listWorkflowRunStepsAction` and `exportWorkflowRunDetailAction` now return `quotaPause` derived from active quota wait payload.
- Added reconciliation helper to quota service:
  - `workflowStepQuotaService.reconcileUsagePeriod(tenant, periodStart, periodEnd)` compares counter usage to step ledger count and returns drift.
- Added support/engineering documentation:
  - `ee/docs/plans/2026-04-28-workflow-step-quota-accounting/OPERATIONS.md` covering quota source/limits, pause/resume behavior, and reconciliation runbook.
- Added diagnostic/observability integration coverage in `server/src/test/integration/workflowStepQuotaService.integration.test.ts`:
  - Reconciliation drift test for `reconcileUsagePeriod()` (`counterUsedCount`, `ledgerStepCount`, `drift`).
  - Structured log assertions for invalid metadata fallback, reservation success, quota exhaustion, and fallback-calendar usage.
- Validation command run:
  - `cd server && npm test -- src/test/integration/workflowStepQuotaService.integration.test.ts` (pass after fixture fix for `workflow_definitions.tenant_id`).
- Added DB runtime quota integration coverage in `server/src/test/integration/workflowRuntimeV2.control.integration.test.ts`:
  - Reserve-before-step-start assertion (no `workflow_run_steps` rows exist before reservation callback returns).
  - Quota exhaustion on second step pauses run with `wait_type='quota'`, keeps `node_path`, and avoids blocked-step row creation.
  - Retry and forEach attempt accounting assertions against `workflow_step_usage_periods.used_count`.
  - Event wait accounting assertion that first entry consumes quota and resume does not double count.
- Added Temporal coverage:
  - `ee/temporal-workflows/src/activities/__tests__/workflow-runtime-v2-activities.test.ts` adds `projectWorkflowRuntimeV2StepStart` tests for reserve-before-start and quota pause projection.
  - `ee/temporal-workflows/src/workflows/__tests__/workflow-runtime-v2-run-workflow.test.ts` adds quota paused short-circuit behavior test (`stepId:null`, `quotaPaused:true`).
- Validation attempts:
  - `cd server && npm test -- src/test/integration/workflowRuntimeV2.control.integration.test.ts` fails in current env with known module resolution issue: `@alga-psa/authorization/kernel` missing from runtime action import graph.
  - `cd ee/temporal-workflows && TEMPORAL_TEST_SKIP_ENV_BOOTSTRAP=1 npm test -- src/activities/__tests__/workflow-runtime-v2-activities.test.ts src/workflows/__tests__/workflow-runtime-v2-run-workflow.test.ts`:
    - activities tests pass.
    - workflow tests fail in current env due package resolution of `@alga-psa/workflows/lib/workflowRuntimeV2TemporalContract` when run in isolation.
- Added manual quota resume integration coverage in `server/src/test/integration/workflowRuntimeV2.control.integration.test.ts`:
  - Resume succeeds when quota is available and runtime re-entry still calls quota reservation.
  - Resume returns `quota_exhausted` response with `usedCount`, `effectiveLimit`, `periodStart`, and `periodEnd` when quota remains exhausted.
- Added unit job coverage in `server/src/test/unit/jobs/workflowQuotaResumeScanHandler.unit.test.ts`:
  - Finite exhausted tenants are skipped while eligible tenants are resolved/resumed.
  - Repeated scans do not resolve/execute the same wait twice once status has moved to `RESOLVED`.
- Validation command run:
  - `cd server && npm test -- src/test/unit/jobs/workflowQuotaResumeScanHandler.unit.test.ts` (pass).
- Added Workflow Control Panel quota usage surfacing:
  - New read-only server action `getWorkflowStepQuotaSummaryAction()` returns current tenant period, limit, used count, remaining count, tier, and sources from `workflowStepQuotaService.resolveQuotaSummary()`.
  - `ee/server/src/components/workflow-designer/WorkflowDesigner.tsx` fetches that action in control-panel mode and renders a compact "Workflow actions" summary with consumed/remaining values, finite-limit progress, and reset date.
  - Added a source-level compatibility re-export at `packages/core/src/rateLimit/index.ts` because Next's dev import map resolves `@alga-psa/core/rateLimit` to `packages/core/src/rateLimit`, while the implementation lives under `packages/core/src/lib/rateLimit`.
- Validation commands run:
  - `cd ee/server && npm run typecheck` (pass).
  - `cd ee/server && NODE_ENV=test npm run test -- src/components/workflow-designer/__tests__/WorkflowDesigner.smoke.test.tsx` (pass; running the same command without `NODE_ENV=test` loads React production test-utils in this workspace and fails before test execution).