feat(webapp): mollifier API GET read-fallback — synthetic primitives + route wiring

[d-cs]

Summary

Synthesise QUEUED/FAILED responses from the mollifier buffer when a TaskRun row hasn't landed in Postgres yet. Wires the synthesis into:

• ApiRetrieveRunPresenter
• v1 trace GET route
• v1 spans GET route
• attempts route gains a GET loader (fixes pre-existing Remix "no loader" 400)

The readFallback infra itself lives on the trigger PR (consumed by IdempotencyKeyConcern); this PR adds the route-level synthetic-rendering primitives.

Stacked on the replay PR.

Test plan

• `pnpm run typecheck --filter webapp` passes
• `pnpm run test --filter webapp test/mollifierSyntheticRedirectInfo.test.ts` passes
• `pnpm run test --filter webapp test/mollifierSyntheticSpanRun.test.ts` passes

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Latest commit: 2b09d20

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[coderabbitai]

Walkthrough

This pull request implements a mollifier API read-fallback that serves synthetic run, trace, and span responses for runs present only in the mollifier buffer. It adds synthetic builders (span/trace and UI SpanRun), integrates a Postgres-first lookup with mollifier fallback in the retrieve presenter, updates /trace, /spans/:spanId, and /events routes to branch on resolved source and return synthetic bodies for buffered runs, provides redirect-info reconstruction for buffered snapshots, and adds comprehensive Vitest coverage.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 55.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Description check	❓ Inconclusive	The description provides clear summary, test plan, and implementation context, but is missing the required sections from the template (Closes issue, Changelog, Screenshots).	Add missing template sections: link the related issue number with 'Closes #', include a brief changelog entry describing changes, and note if screenshots are needed for this backend/API change.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main changes: adding synthetic API response primitives and wiring mollifier read-fallback into routes.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch mollifier-phase-3-reads

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[devin-ai-integration]

Devin Review found 1 new potential issue.

View 31 additional findings in Devin Review.

[coderabbitai]

🧹 Nitpick comments (1)

apps/webapp/test/mollifierReadFallback.test.ts (1)

440-463: 💤 Low value

Minor test overlap with lines 330-350.

This test ("extracts batchId from the nested snapshot.batch object (not the flat key)") covers essentially the same positive case as lines 330-350 ("extracts batchId from the snapshot's nested batch object (engine.trigger shape)"). Consider consolidating into a single test or ensuring they test meaningfully different aspects—the regression comment here adds value but the assertions are identical.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@apps/webapp/test/mollifierReadFallback.test.ts` around lines 440 - 463, The
two tests duplicate the same positive assertion about extracting batchId from
the nested snapshot.batch object; consolidate or differentiate them by keeping
one of the tests (either "extracts batchId from the nested snapshot.batch object
(not the flat key)" or "extracts batchId from the snapshot's nested batch object
(engine.trigger shape)") and removing the other, or modify one to cover a
distinct scenario (e.g., ensure readFallback returns undefined when only flat
batchId is present or when batch is missing). Update the assertions around
findRunByIdWithMollifierFallback and the BufferEntry payload accordingly so each
test verifies a unique behavior.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@apps/webapp/test/mollifierReadFallback.test.ts`:
- Around line 440-463: The two tests duplicate the same positive assertion about
extracting batchId from the nested snapshot.batch object; consolidate or
differentiate them by keeping one of the tests (either "extracts batchId from
the nested snapshot.batch object (not the flat key)" or "extracts batchId from
the snapshot's nested batch object (engine.trigger shape)") and removing the
other, or modify one to cover a distinct scenario (e.g., ensure readFallback
returns undefined when only flat batchId is present or when batch is missing).
Update the assertions around findRunByIdWithMollifierFallback and the
BufferEntry payload accordingly so each test verifies a unique behavior.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: af31bf01-2000-4465-a39f-d934a4cb1de2

📥 Commits

Reviewing files that changed from the base of the PR and between c5e3ddb and 2b09d20.

📒 Files selected for processing (2)

• apps/webapp/app/v3/mollifier/readFallback.server.ts
• apps/webapp/test/mollifierReadFallback.test.ts

📜 Review details

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (12)

• GitHub Check: webapp / 🧪 Unit Tests: Webapp (5, 8)
• GitHub Check: webapp / 🧪 Unit Tests: Webapp (7, 8)
• GitHub Check: typecheck / typecheck
• GitHub Check: webapp / 🧪 Unit Tests: Webapp (8, 8)
• GitHub Check: webapp / 🧪 Unit Tests: Webapp (6, 8)
• GitHub Check: webapp / 🧪 Unit Tests: Webapp (4, 8)
• GitHub Check: webapp / 🧪 Unit Tests: Webapp (2, 8)
• GitHub Check: webapp / 🧪 Unit Tests: Webapp (3, 8)
• GitHub Check: webapp / 🧪 Unit Tests: Webapp (1, 8)
• GitHub Check: e2e-webapp / 🧪 E2E Tests: Webapp
• GitHub Check: 🛡️ E2E Auth Tests (full)
• GitHub Check: Analyze (javascript-typescript)

🧰 Additional context used

📓 Path-based instructions (10)

**/*.{ts,tsx}

📄 CodeRabbit inference engine (.github/copilot-instructions.md)

**/*.{ts,tsx}: Use types over interfaces for TypeScript
Avoid using enums; prefer string unions or const objects instead

Files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts
• apps/webapp/test/mollifierReadFallback.test.ts

{packages/core,apps/webapp}/**/*.{ts,tsx}

📄 CodeRabbit inference engine (.github/copilot-instructions.md)

Use zod for validation in packages/core and apps/webapp

Files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts
• apps/webapp/test/mollifierReadFallback.test.ts

**/*.{ts,tsx,js,jsx}

📄 CodeRabbit inference engine (.github/copilot-instructions.md)

Use function declarations instead of default exports

**/*.{ts,tsx,js,jsx}: Prefer static imports over dynamic imports. Only use dynamic import() when circular dependencies cannot be resolved otherwise, code splitting is needed for performance, or the module must be loaded conditionally at runtime.
Import from @trigger.dev/core using subpaths only - never import from the root.
When writing Trigger.dev tasks, always import from @trigger.dev/sdk. Never use @trigger.dev/sdk/v3 or deprecated client.defineJob.
Add agentcrumbs markers (// @Crumbs or `#region `@crumbs) as you write code, not just when debugging. They stay on the branch throughout development and are stripped by agentcrumbs strip before merge.

Files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts
• apps/webapp/test/mollifierReadFallback.test.ts

**/*.ts

📄 CodeRabbit inference engine (.cursor/rules/otel-metrics.mdc)

**/*.ts: When creating or editing OTEL metrics (counters, histograms, gauges), ensure metric attributes have low cardinality by using only enums, booleans, bounded error codes, or bounded shard IDs
Do not use high-cardinality attributes in OTEL metrics such as UUIDs/IDs (envId, userId, runId, projectId, organizationId), unbounded integers (itemCount, batchSize, retryCount), timestamps (createdAt, startTime), or free-form strings (errorMessage, taskName, queueName)
When exporting OTEL metrics via OTLP to Prometheus, be aware that the exporter automatically adds unit suffixes to metric names (e.g., 'my_duration_ms' becomes 'my_duration_ms_milliseconds', 'my_counter' becomes 'my_counter_total'). Account for these transformations when writing Grafana dashboards or Prometheus queries

Files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts
• apps/webapp/test/mollifierReadFallback.test.ts

apps/webapp/**/*.{ts,tsx}

📄 CodeRabbit inference engine (.cursor/rules/webapp.mdc)

apps/webapp/**/*.{ts,tsx}: Access environment variables through the env export of env.server.ts instead of directly accessing process.env
Use subpath exports from @trigger.dev/core package instead of importing from the root @trigger.dev/core path

Use named constants for sentinel/placeholder values (e.g. const UNSET_VALUE = '__unset__') instead of raw string literals scattered across comparisons

Files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts
• apps/webapp/test/mollifierReadFallback.test.ts

apps/webapp/**/*.server.ts

📄 CodeRabbit inference engine (apps/webapp/CLAUDE.md)

apps/webapp/**/*.server.ts: Never use request.signal for detecting client disconnects. Use getRequestAbortSignal() from app/services/httpAsyncStorage.server.ts instead, which is wired directly to Express res.on('close') and fires reliably
Access environment variables via env export from app/env.server.ts. Never use process.env directly
Always use findFirst instead of findUnique in Prisma queries. findUnique has an implicit DataLoader that batches concurrent calls and has active bugs even in Prisma 6.x (uppercase UUIDs returning null, composite key SQL correctness issues, 5-10x worse performance). findFirst is never batched and avoids this entire class of issues

Files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts

**/*.{js,jsx,ts,tsx,json,md,yml,yaml}

📄 CodeRabbit inference engine (AGENTS.md)

Code formatting must be enforced using Prettier before committing

Files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts
• apps/webapp/test/mollifierReadFallback.test.ts

**/*.{test,spec}.{ts,tsx}

📄 CodeRabbit inference engine (.github/copilot-instructions.md)

Use vitest for all tests in the Trigger.dev repository

Files:

• apps/webapp/test/mollifierReadFallback.test.ts

apps/webapp/**/*.test.{ts,tsx}

📄 CodeRabbit inference engine (.cursor/rules/webapp.mdc)

Do not import env.server.ts directly or indirectly into test files; instead pass environment-dependent values through options/parameters to make code testable

For testable code, never import env.server.ts in test files. Pass configuration as options instead (e.g., realtimeClient.server.ts takes config as constructor arg, realtimeClientGlobal.server.ts creates singleton with env config)

Files:

• apps/webapp/test/mollifierReadFallback.test.ts

**/*.test.{ts,tsx,js,jsx}

📄 CodeRabbit inference engine (AGENTS.md)

**/*.test.{ts,tsx,js,jsx}: Test files should live beside the files under test and use descriptive describe and it blocks
Unit tests should use vitest framework
Tests should avoid mocks or stubs and use helpers from @internal/testcontainers when Redis or Postgres are needed

**/*.test.{ts,tsx,js,jsx}: Never mock anything in tests - use testcontainers instead.
Test files should be placed next to source files (e.g., MyService.ts -> MyService.test.ts).

Files:

• apps/webapp/test/mollifierReadFallback.test.ts

🧠 Learnings (11)

📚 Learning: 2026-03-22T13:26:12.060Z

Learnt from: ericallam
Repo: triggerdotdev/trigger.dev PR: 3244
File: apps/webapp/app/components/code/TextEditor.tsx:81-86
Timestamp: 2026-03-22T13:26:12.060Z
Learning: In the triggerdotdev/trigger.dev codebase, do not flag `navigator.clipboard.writeText(...)` calls for `missing-await`/`unhandled-promise` issues. These clipboard writes are intentionally invoked without `await` and without `catch` handlers across the project; keep that behavior consistent when reviewing TypeScript/TSX files (e.g., usages like in `apps/webapp/app/components/code/TextEditor.tsx`).

Applied to files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts
• apps/webapp/test/mollifierReadFallback.test.ts

📚 Learning: 2026-03-22T19:24:14.403Z

Learnt from: matt-aitken
Repo: triggerdotdev/trigger.dev PR: 3187
File: apps/webapp/app/v3/services/alerts/deliverErrorGroupAlert.server.ts:200-204
Timestamp: 2026-03-22T19:24:14.403Z
Learning: In the triggerdotdev/trigger.dev codebase, webhook URLs are not expected to contain embedded credentials/secrets (e.g., fields like `ProjectAlertWebhookProperties` should only hold credential-free webhook endpoints). During code review, if you see logging or inclusion of raw webhook URLs in error messages, do not automatically treat it as a credential-leak/secrets-in-logs issue by default—first verify the URL does not contain embedded credentials (for example, no username/password in the URL, no obvious secret/token query params or fragments). If the URL is credential-free per this project’s conventions, allow the logging.

Applied to files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts
• apps/webapp/test/mollifierReadFallback.test.ts

📚 Learning: 2026-05-18T08:21:27.694Z

Learnt from: d-cs
Repo: triggerdotdev/trigger.dev PR: 3632
File: apps/webapp/sentry.server.ts:4-21
Timestamp: 2026-05-18T08:21:27.694Z
Learning: When handling Prisma error P1001 ("Can't reach database server") in TypeScript, don’t assume a single error shape. Prisma can surface P1001 via two different error classes/fields: `PrismaClientKnownRequestError` exposes it as `err.code === "P1001"` (common during mid-query connection drops), while `PrismaClientInitializationError` exposes it as `err.errorCode === "P1001"` (common on client startup failure). Therefore, predicates should use `err.code === "P1001" || err.errorCode === "P1001"`. Do not flag `err.code === "P1001"` as “unreachable/never matches,” as it is expected in production.

Applied to files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts
• apps/webapp/test/mollifierReadFallback.test.ts

📚 Learning: 2026-05-18T08:21:27.694Z

Learnt from: d-cs
Repo: triggerdotdev/trigger.dev PR: 3632
File: apps/webapp/sentry.server.ts:4-21
Timestamp: 2026-05-18T08:21:27.694Z
Learning: When handling Prisma errors for P1001 ("Can't reach database server"), do not assume it only appears under a single property name. Prisma may surface P1001 via either `PrismaClientKnownRequestError` (`err.code === "P1001"`, e.g., mid-query connection drops) or `PrismaClientInitializationError` (`err.errorCode === "P1001"`, e.g., client startup connection failure). To reliably detect the condition, check `err.code === "P1001" || err.errorCode === "P1001"`, and avoid review rules that would incorrectly flag `err.code === "P1001"` as unreachable/never-matching.

Applied to files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts
• apps/webapp/test/mollifierReadFallback.test.ts

📚 Learning: 2026-03-29T19:16:28.864Z

Learnt from: nicktrn
Repo: triggerdotdev/trigger.dev PR: 3291
File: apps/webapp/app/v3/featureFlags.ts:53-65
Timestamp: 2026-03-29T19:16:28.864Z
Learning: When reviewing TypeScript code that uses Zod v3, treat `z.coerce.*()` schemas as their direct Zod type (e.g., `z.coerce.boolean()` returns a `ZodBoolean` with `_def.typeName === "ZodBoolean"`) rather than a `ZodEffects`. Only `.preprocess()`, `.refine()`/`.superRefine()`, and `.transform()` are expected to wrap schemas in `ZodEffects`. Therefore, in reviewers’ logic like `getFlagControlType`, do not flag/unblock failures that require unwrapping `ZodEffects` when the input schema is a `z.coerce.*` schema.

Applied to files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts

📚 Learning: 2026-05-05T09:38:02.512Z

Learnt from: d-cs
Repo: triggerdotdev/trigger.dev PR: 3523
File: apps/webapp/app/routes/api.v3.batches.ts:178-181
Timestamp: 2026-05-05T09:38:02.512Z
Learning: When reviewing code that catches `ServiceValidationError` in `*.server.ts` files, do not blindly forward `error.status` to HTTP responses, because SVEs may be thrown with non-default statuses (e.g., 400/500) and forwarding them can cause client-visible behavioral regressions (e.g., surfacing 500s to clients). Prefer a safe default response status of `error.status ?? 422`, but only after confirming via the reachable call graph that the caught `ServiceValidationError` instances are expected to carry those non-default statuses; otherwise, normalize to `422` to avoid unexpected client-visible 5xx behavior.

Applied to files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts

📚 Learning: 2026-05-12T21:04:05.815Z

Learnt from: ericallam
Repo: triggerdotdev/trigger.dev PR: 3542
File: apps/webapp/app/components/sessions/v1/SessionStatus.tsx:1-3
Timestamp: 2026-05-12T21:04:05.815Z
Learning: In this Remix + TypeScript codebase, do not flag a server/client boundary violation when a file imports only types from a module matching `*.server`.

Specifically, it’s safe to import types using `import type { Foo } from "*.server"` or `import { type Foo } from "*.server"` because TypeScript erases type-only imports at compile time and they emit no JavaScript, so they won’t cross the Remix server/client bundle boundary.

Only raise the boundary concern for value imports (e.g., `import { Foo }` without `type`, or `import Foo`), since those produce JavaScript output.

Applied to files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts
• apps/webapp/test/mollifierReadFallback.test.ts

📚 Learning: 2026-05-14T08:21:07.614Z

Learnt from: d-cs
Repo: triggerdotdev/trigger.dev PR: 3614
File: apps/webapp/app/v3/mollifier/mollifierGate.server.ts:48-52
Timestamp: 2026-05-14T08:21:07.614Z
Learning: When using Trigger.dev v3 feature flags in the webapp, prefer the existing per-org gating mechanism supported by `flag()` via the `overrides` argument. Pass `Organization.featureFlags` (from `environment.organization.featureFlags`) as the `overrides` value; overrides must take precedence over the global `featureFlag` row. Do not require schema changes or add an `orgId` field to `FlagsOptions` for per-org gating—use the overrides pattern consistently (e.g., in gate flows like `resolveOrgFlag` and any server code that threads `environment.organization.featureFlags` into the gate call).

Applied to files:

• apps/webapp/app/v3/mollifier/readFallback.server.ts

📚 Learning: 2026-05-07T12:25:18.271Z

Learnt from: d-cs
Repo: triggerdotdev/trigger.dev PR: 3531
File: apps/webapp/test/sentryTraceContext.server.test.ts:9-47
Timestamp: 2026-05-07T12:25:18.271Z
Learning: In the triggerdotdev/trigger.dev webapp test suite, it is acceptable to leave `createInMemoryTracing()` calls that register a global `NodeTracerProvider` without `afterEach`/`afterAll` teardown. Do not flag this as a test-ordering risk when the code follows the established pattern used across webapp tests (e.g., replication service/benchmark/backfiller tests). This is considered safe because `trace.getActiveSpan()` when called outside a `context.with(...)` block reads `AsyncLocalStorage.getStore()` (undefined when no `run()` scope exists), so it falls back to `ROOT_CONTEXT` with no attached span—regardless of which provider is registered.

Applied to files:

• apps/webapp/test/mollifierReadFallback.test.ts

📚 Learning: 2026-05-28T20:02:10.647Z

Learnt from: myftija
Repo: triggerdotdev/trigger.dev PR: 3772
File: apps/webapp/test/findOrCreateBackgroundWorker.test.ts:1-1
Timestamp: 2026-05-28T20:02:10.647Z
Learning: In the triggerdotdev/trigger.dev monorepo, for the `apps/webapp` package use the established convention of storing Vitest tests (unit, integration, and e2e) under `apps/webapp/test/` rather than colocating them next to source files. Do not flag files located in `apps/webapp/test/` as violating any rule that says to colocate tests with source.

Applied to files:

• apps/webapp/test/mollifierReadFallback.test.ts

📚 Learning: 2026-05-18T14:40:02.173Z

Learnt from: ericallam
Repo: triggerdotdev/trigger.dev PR: 3658
File: packages/core/src/v3/realtimeStreams/manager.test.ts:1-147
Timestamp: 2026-05-18T14:40:02.173Z
Learning: In the triggerdotdev/trigger.dev repo, the policy “Never mock anything — use testcontainers instead” should only be enforced for integration tests that interact with real external services (e.g., Redis, Postgres) via actual infrastructure. For unit tests that exercise pure in-memory logic (e.g., cache semantics) it is OK to stub collaborators such as `ApiClient` using Vitest (`vi.fn()`) to assert call counts or control behavior. Do not flag `vi.fn()`-based `ApiClient` stubs in unit tests as violations of the testcontainers policy.

Applied to files:

• apps/webapp/test/mollifierReadFallback.test.ts

🔇 Additional comments (9)

apps/webapp/app/v3/mollifier/readFallback.server.ts (3)

3-4: LGTM!

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55-63: LGTM!

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158-170: LGTM!

apps/webapp/test/mollifierReadFallback.test.ts (6)

140-141: LGTM!

Also applies to: 164-164

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198-232: LGTM!

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234-263: LGTM!

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330-367: LGTM!

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465-485: LGTM!

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487-534: LGTM!