diff --git a/services/platform-service/src/modules/fleet/artifacts-blob.ts b/services/platform-service/src/modules/fleet/artifacts-blob.ts
new file mode 100644
index 00000000..93a98f04
--- /dev/null
+++ b/services/platform-service/src/modules/fleet/artifacts-blob.ts
@@ -0,0 +1,112 @@
+/**
+ * Fleet artifacts — blob wiring (§13/§26).
+ *
+ * Large run outputs (logs, coverage, screenshots, build output) are written to
+ * blob storage; only a POINTER (blob key + size/content-type/sha256) is persisted
+ * in the `fleet_artifacts` Cosmos container. The bytes NEVER touch Cosmos — this
+ * keeps documents well under the doc-size / RU ceilings no matter how large a log
+ * gets. Read access is granted via a short-lived SAS URL minted on demand from the
+ * stored key (the URL itself is never persisted).
+ *
+ * Blob key scheme (deterministic, product- and job-scoped):
+ *   fleet/<productId>/<jobId>/<artifactId>-<kind>
+ */
+
+import { createHash, randomUUID } from 'node:crypto';
+import { getBucket, generateSasUrl } from '../../lib/blob.js';
+import * as repo from './repository.js';
+import { FleetArtifactDocSchema, type FleetArtifactDoc, type FleetArtifactKind } from './types.js';
+
+/** Container holding all fleet run-output blobs. */
+export const FLEET_ARTIFACTS_CONTAINER = 'fleet-artifacts';
+
+/** SAS read-URL lifetime. Short-lived — callers re-issue via getArtifactDownload. */
+export const ARTIFACT_SAS_TTL_MINUTES = 15;
+
+/** A persisted artifact pointer paired with a freshly-minted SAS read URL. */
+export interface ArtifactWithDownload {
+  artifact: FleetArtifactDoc;
+  downloadUrl: string;
+}
+
+export interface UploadArtifactArgs {
+  productId: string;
+  jobId: string;
+  kind: FleetArtifactKind;
+  bytes: Buffer;
+  contentType: string;
+  runId?: string;
+}
+
+/** Deterministic blob key for an artifact. */
+export function artifactBlobKey(
+  productId: string,
+  jobId: string,
+  artifactId: string,
+  kind: FleetArtifactKind
+): string {
+  return `fleet/${productId}/${jobId}/${artifactId}-${kind}`;
+}
+
+/**
+ * Upload artifact bytes to blob storage and persist the Cosmos pointer.
+ * Returns the pointer doc plus a short-lived SAS read URL. The bytes live only in
+ * blob — the returned doc carries no inline payload.
+ */
+export async function uploadArtifact(args: UploadArtifactArgs): Promise<ArtifactWithDownload> {
+  const id = `art_${randomUUID()}`;
+  const blobKey = artifactBlobKey(args.productId, args.jobId, id, args.kind);
+
+  const bucket = await getBucket(FLEET_ARTIFACTS_CONTAINER);
+  const meta = await bucket.upload(blobKey, args.bytes, { contentType: args.contentType });
+
+  const sha256 = createHash('sha256').update(args.bytes).digest('hex');
+
+  const doc: FleetArtifactDoc = FleetArtifactDocSchema.parse({
+    id,
+    productId: args.productId,
+    jobId: args.jobId,
+    runId: args.runId,
+    kind: args.kind,
+    blobKey,
+    contentType: args.contentType,
+    sizeBytes: meta.size ?? args.bytes.length,
+    sha256,
+    createdAt: new Date().toISOString(),
+  });
+
+  const artifact = await repo.createArtifact(doc);
+  const downloadUrl = await issueDownloadUrl(blobKey);
+  return { artifact, downloadUrl };
+}
+
+/**
+ * Re-issue a fresh short-lived SAS read URL for an existing artifact, scoped to
+ * its owning product. Returns null when the artifact does not exist for that product.
+ */
+export async function getArtifactDownload(
+  id: string,
+  productId: string
+): Promise<ArtifactWithDownload | null> {
+  const artifact = await repo.getArtifact(id, productId);
+  if (!artifact) return null;
+  const downloadUrl = await issueDownloadUrl(artifact.blobKey);
+  return { artifact, downloadUrl };
+}
+
+/**
+ * Delete an artifact's pointer (and its backing blob), scoped to its owning
+ * product. Returns false when nothing matched.
+ */
+export async function deleteArtifact(id: string, productId: string): Promise<boolean> {
+  const artifact = await repo.getArtifact(id, productId);
+  if (!artifact) return false;
+  const bucket = await getBucket(FLEET_ARTIFACTS_CONTAINER);
+  await bucket.delete(artifact.blobKey);
+  await repo.deleteArtifact(id, productId);
+  return true;
+}
+
+function issueDownloadUrl(blobKey: string): Promise<string> {
+  return generateSasUrl(FLEET_ARTIFACTS_CONTAINER, blobKey, 'r', ARTIFACT_SAS_TTL_MINUTES);
+}
diff --git a/services/platform-service/src/modules/fleet/artifacts.test.ts b/services/platform-service/src/modules/fleet/artifacts.test.ts
new file mode 100644
index 00000000..b96c1b22
--- /dev/null
+++ b/services/platform-service/src/modules/fleet/artifacts.test.ts
@@ -0,0 +1,251 @@
+/**
+ * Fleet artifacts — blob wiring (§13/§26).
+ *
+ * Runs on the in-memory datastore + in-memory blob provider. The central
+ * guarantee under test: artifact BYTES live in blob storage and only a POINTER
+ * (blobKey + size/content-type/sha256) is persisted in Cosmos — never the bytes.
+ *
+ * Auth + productId resolution are mocked exactly as the items / fleet routes
+ * tests do. The non-route service tests don't touch those mocks.
+ */
+
+// Select the in-memory blob provider before the storage singleton is created.
+process.env.STORAGE_PROVIDER = 'memory';
+
+import Fastify, { type FastifyInstance } from 'fastify';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { MemoryDatastoreProvider } from '@bytelyst/datastore';
+import { _resetBlobClient, getBucket } from '@bytelyst/blob';
+import { _resetDatastoreProvider, setProvider } from '../../lib/datastore.js';
+import * as repo from './repository.js';
+import * as artifactsBlob from './artifacts-blob.js';
+
+vi.mock('../../lib/auth.js', () => ({
+  extractAuth: vi.fn(async () => ({ sub: 'user_1', role: 'admin' })),
+}));
+vi.mock('../../lib/request-context.js', () => ({
+  getRequestProductId: () => 'lysnrai',
+}));
+
+const PID = 'lysnrai';
+
+/** Fields that would indicate bytes were (wrongly) inlined into the Cosmos doc. */
+const INLINE_PAYLOAD_FIELDS = [
+  'contentBase64',
+  'payload',
+  'bytes',
+  'data',
+  'content',
+  'body',
+  'blob',
+];
+
+async function buildApp(): Promise<FastifyInstance> {
+  const { fleetRoutes } = await import('./routes.js');
+  const app = Fastify({ logger: false });
+  await app.register(fleetRoutes, { prefix: '/api' });
+  return app;
+}
+
+beforeEach(() => {
+  setProvider(new MemoryDatastoreProvider());
+  _resetBlobClient();
+});
+afterEach(() => {
+  _resetDatastoreProvider();
+  _resetBlobClient();
+  vi.clearAllMocks();
+});
+
+describe('fleet artifacts — blob service', () => {
+  it('upload writes bytes to blob and persists a pointer-only Cosmos doc', async () => {
+    const bytes = Buffer.from('hello log output');
+    const { artifact, downloadUrl } = await artifactsBlob.uploadArtifact({
+      productId: PID,
+      jobId: 'j1',
+      kind: 'log',
+      bytes,
+      contentType: 'text/plain',
+    });
+
+    // pointer metadata
+    expect(artifact.productId).toBe(PID);
+    expect(artifact.jobId).toBe('j1');
+    expect(artifact.kind).toBe('log');
+    expect(artifact.contentType).toBe('text/plain');
+    expect(artifact.sizeBytes).toBe(bytes.length);
+    expect(artifact.blobKey).toBe(`fleet/${PID}/j1/${artifact.id}-log`);
+    expect(artifact.sha256).toMatch(/^[0-9a-f]{64}$/);
+    expect(downloadUrl).toContain('signed=true');
+
+    // the persisted Cosmos doc carries NO inline payload — bytes are not in Cosmos
+    const stored = await repo.getArtifact(artifact.id, PID);
+    expect(stored).not.toBeNull();
+    for (const field of INLINE_PAYLOAD_FIELDS) {
+      expect(stored).not.toHaveProperty(field);
+    }
+    // only the pointer/metadata fields are present
+    expect(stored).toMatchObject({
+      id: artifact.id,
+      productId: PID,
+      jobId: 'j1',
+      kind: 'log',
+      blobKey: artifact.blobKey,
+      contentType: 'text/plain',
+      sizeBytes: bytes.length,
+    });
+
+    // the actual bytes DO live in blob storage
+    const bucket = await getBucket(artifactsBlob.FLEET_ARTIFACTS_CONTAINER);
+    const fromBlob = await bucket.download(artifact.blobKey);
+    expect(fromBlob.toString()).toBe('hello log output');
+  });
+
+  it('list by job is partition-isolated (returns only that job)', async () => {
+    await artifactsBlob.uploadArtifact({
+      productId: PID,
+      jobId: 'jA',
+      kind: 'log',
+      bytes: Buffer.from('a1'),
+      contentType: 'text/plain',
+    });
+    await artifactsBlob.uploadArtifact({
+      productId: PID,
+      jobId: 'jA',
+      kind: 'coverage',
+      bytes: Buffer.from('a2'),
+      contentType: 'application/json',
+    });
+    await artifactsBlob.uploadArtifact({
+      productId: PID,
+      jobId: 'jB',
+      kind: 'screenshot',
+      bytes: Buffer.from('b1'),
+      contentType: 'image/png',
+    });
+
+    const a = await repo.listArtifactsByJob('jA');
+    const b = await repo.listArtifactsByJob('jB');
+    expect(a).toHaveLength(2);
+    expect(a.every(x => x.jobId === 'jA')).toBe(true);
+    expect(b).toHaveLength(1);
+    expect(b[0].jobId).toBe('jB');
+  });
+
+  it('get re-issues a fresh SAS URL; a large (>Cosmos-safe) payload still succeeds (blob offload)', async () => {
+    // 3 MB — comfortably beyond the ~2 MB Cosmos document ceiling, so this can
+    // only succeed because the bytes are offloaded to blob, not stored inline.
+    const big = Buffer.alloc(3 * 1024 * 1024, 0x61);
+    const { artifact } = await artifactsBlob.uploadArtifact({
+      productId: PID,
+      jobId: 'jbig',
+      kind: 'build',
+      bytes: big,
+      contentType: 'application/octet-stream',
+    });
+    expect(artifact.sizeBytes).toBe(3 * 1024 * 1024);
+
+    const dl = await artifactsBlob.getArtifactDownload(artifact.id, PID);
+    expect(dl).not.toBeNull();
+    expect(dl?.downloadUrl).toContain('signed=true');
+    expect(dl?.downloadUrl).toContain(artifact.blobKey);
+
+    // product-scoped: a foreign product cannot fetch it
+    expect(await artifactsBlob.getArtifactDownload(artifact.id, 'other-product')).toBeNull();
+    // bytes round-trip from blob at full size
+    const bucket = await getBucket(artifactsBlob.FLEET_ARTIFACTS_CONTAINER);
+    expect((await bucket.download(artifact.blobKey)).length).toBe(3 * 1024 * 1024);
+  });
+
+  it('delete removes both the pointer and the backing blob', async () => {
+    const { artifact } = await artifactsBlob.uploadArtifact({
+      productId: PID,
+      jobId: 'jd',
+      kind: 'other',
+      bytes: Buffer.from('tmp'),
+      contentType: 'text/plain',
+    });
+    const bucket = await getBucket(artifactsBlob.FLEET_ARTIFACTS_CONTAINER);
+    expect(await bucket.exists(artifact.blobKey)).toBe(true);
+
+    expect(await artifactsBlob.deleteArtifact(artifact.id, PID)).toBe(true);
+    expect(await repo.getArtifact(artifact.id, PID)).toBeNull();
+    expect(await bucket.exists(artifact.blobKey)).toBe(false);
+
+    // idempotent / unknown → false
+    expect(await artifactsBlob.deleteArtifact(artifact.id, PID)).toBe(false);
+  });
+});
+
+describe('fleet artifacts — routes (fastify inject)', () => {
+  const b64 = (s: string) => Buffer.from(s).toString('base64');
+
+  it('POST upload → 201 with pointer + SAS; GET list → the pointer; bytes not echoed', async () => {
+    const app = await buildApp();
+    const res = await app.inject({
+      method: 'POST',
+      url: '/api/fleet/jobs/jr1/artifacts',
+      payload: { kind: 'log', contentType: 'text/plain', contentBase64: b64('route log bytes') },
+    });
+    expect(res.statusCode).toBe(201);
+    const body = JSON.parse(res.body);
+    expect(body.artifact.jobId).toBe('jr1');
+    expect(body.artifact.blobKey).toBe(`fleet/${PID}/jr1/${body.artifact.id}-log`);
+    expect(body.artifact.sizeBytes).toBe(Buffer.from('route log bytes').length);
+    expect(body.downloadUrl).toContain('signed=true');
+    for (const field of INLINE_PAYLOAD_FIELDS) {
+      expect(body.artifact).not.toHaveProperty(field);
+    }
+
+    const list = await app.inject({ method: 'GET', url: '/api/fleet/jobs/jr1/artifacts' });
+    expect(list.statusCode).toBe(200);
+    const arts = JSON.parse(list.body).artifacts;
+    expect(arts).toHaveLength(1);
+    expect(arts[0].id).toBe(body.artifact.id);
+  });
+
+  it('GET /fleet/artifacts/:id returns a fresh SAS URL; DELETE removes it', async () => {
+    const app = await buildApp();
+    const up = await app.inject({
+      method: 'POST',
+      url: '/api/fleet/jobs/jr2/artifacts',
+      payload: {
+        kind: 'coverage',
+        contentType: 'application/json',
+        contentBase64: b64('{"pct":91}'),
+      },
+    });
+    const id = JSON.parse(up.body).artifact.id as string;
+
+    const got = await app.inject({ method: 'GET', url: `/api/fleet/artifacts/${id}` });
+    expect(got.statusCode).toBe(200);
+    const gotBody = JSON.parse(got.body);
+    expect(gotBody.artifact.id).toBe(id);
+    expect(gotBody.downloadUrl).toContain('signed=true');
+
+    const del = await app.inject({ method: 'DELETE', url: `/api/fleet/artifacts/${id}` });
+    expect(del.statusCode).toBe(200);
+    expect(JSON.parse(del.body).deleted).toBe(true);
+
+    // gone now
+    const after = await app.inject({ method: 'GET', url: `/api/fleet/artifacts/${id}` });
+    expect(after.statusCode).toBe(404);
+  });
+
+  it('rejects an invalid upload body (400) and unknown artifact ids (404)', async () => {
+    const app = await buildApp();
+
+    const bad = await app.inject({
+      method: 'POST',
+      url: '/api/fleet/jobs/jr3/artifacts',
+      payload: { contentBase64: b64('x') }, // missing kind
+    });
+    expect(bad.statusCode).toBe(400);
+
+    const getMissing = await app.inject({ method: 'GET', url: '/api/fleet/artifacts/nope' });
+    expect(getMissing.statusCode).toBe(404);
+
+    const delMissing = await app.inject({ method: 'DELETE', url: '/api/fleet/artifacts/nope' });
+    expect(delMissing.statusCode).toBe(404);
+  });
+});
diff --git a/services/platform-service/src/modules/fleet/repository.test.ts b/services/platform-service/src/modules/fleet/repository.test.ts
index cdf5b6b5..e7c393dc 100644
--- a/services/platform-service/src/modules/fleet/repository.test.ts
+++ b/services/platform-service/src/modules/fleet/repository.test.ts
@@ -171,17 +171,29 @@ describe('fleet repository', () => {
     expect(events.map(e => e.type)).toEqual(['submitted', 'assigned', 'transition']);
   });
 
-  it('artifacts: create + list', async () => {
+  it('artifacts: create + listByJob + get + delete (pointer only)', async () => {
     await repo.createArtifact({
       id: 'art_1',
       productId: PID,
       jobId: 'j',
       kind: 'coverage',
-      blobUrl: 'https://b/x',
+      blobKey: 'fleet/lysnrai/j/art_1-coverage',
+      contentType: 'application/json',
+      sizeBytes: 42,
       createdAt: now,
     });
-    const arts = await repo.listArtifacts('j');
+    const arts = await repo.listArtifactsByJob('j');
     expect(arts).toHaveLength(1);
-    expect(arts[0].blobUrl).toBe('https://b/x');
+    expect(arts[0].blobKey).toBe('fleet/lysnrai/j/art_1-coverage');
+
+    // get is product-scoped (wrong product → null)
+    expect((await repo.getArtifact('art_1', PID))?.contentType).toBe('application/json');
+    expect(await repo.getArtifact('art_1', 'other-product')).toBeNull();
+
+    // delete returns the removed doc and clears the partition
+    const removed = await repo.deleteArtifact('art_1', PID);
+    expect(removed?.id).toBe('art_1');
+    expect(await repo.listArtifactsByJob('j')).toHaveLength(0);
+    expect(await repo.deleteArtifact('art_1', PID)).toBeNull();
   });
 });
diff --git a/services/platform-service/src/modules/fleet/repository.ts b/services/platform-service/src/modules/fleet/repository.ts
index e9fb0373..a298855f 100644
--- a/services/platform-service/src/modules/fleet/repository.ts
+++ b/services/platform-service/src/modules/fleet/repository.ts
@@ -247,12 +247,39 @@ export async function listEvents(jobId: string): Promise<FleetEventDoc[]> {
   return docs;
 }
 
-// ── Artifacts ─────────────────────────────────────────────────────────────────
+// ── Artifacts (pointers only — bytes live in blob, never Cosmos; §13) ──────────
 
 export async function createArtifact(doc: FleetArtifactDoc): Promise<FleetArtifactDoc> {
   return artifacts().create(doc);
 }
 
-export async function listArtifacts(jobId: string): Promise<FleetArtifactDoc[]> {
+/** All artifact pointers for a job, oldest-first (single partition — pk `/jobId`). */
+export async function listArtifactsByJob(jobId: string): Promise<FleetArtifactDoc[]> {
   return artifacts().findMany({ filter: { jobId }, sort: { createdAt: 1 } });
 }
+
+/**
+ * Fetch one artifact pointer by id, scoped to its owning product. The container
+ * is partitioned by `/jobId` (not `/productId`), so this is a small filtered
+ * query rather than a point read; the `productId` predicate enforces ownership
+ * for the by-id routes (foreign-product / unknown id → null).
+ */
+export async function getArtifact(id: string, productId: string): Promise<FleetArtifactDoc | null> {
+  const found = await artifacts().findMany({ filter: { id, productId }, limit: 1 });
+  return found[0] ?? null;
+}
+
+/**
+ * Delete an artifact pointer by id, scoped to its owning product. Resolves the
+ * partition (`jobId`) from the located doc, then deletes. Returns the removed doc
+ * (so callers can also clean up the backing blob) or null when not found.
+ */
+export async function deleteArtifact(
+  id: string,
+  productId: string
+): Promise<FleetArtifactDoc | null> {
+  const doc = await getArtifact(id, productId);
+  if (!doc) return null;
+  await artifacts().delete(id, doc.jobId);
+  return doc;
+}
diff --git a/services/platform-service/src/modules/fleet/routes.ts b/services/platform-service/src/modules/fleet/routes.ts
index 0d630aea..12b80706 100644
--- a/services/platform-service/src/modules/fleet/routes.ts
+++ b/services/platform-service/src/modules/fleet/routes.ts
@@ -11,6 +11,10 @@
  * POST   /fleet/factories/heartbeat   factory liveness
  * GET    /fleet/jobs/:id/runs         job run history
  * GET    /fleet/jobs/:id/events       append-only event stream
+ * POST   /fleet/jobs/:id/artifacts    upload a run output (base64 body → blob + pointer)
+ * GET    /fleet/jobs/:id/artifacts    list a job's artifact pointers
+ * GET    /fleet/artifacts/:artifactId pointer + fresh short-lived SAS download URL
+ * DELETE /fleet/artifacts/:artifactId delete pointer (and backing blob)
  *
  * All routes require auth + a resolved productId, exactly like the items module.
  */
@@ -21,6 +25,7 @@ import { BadRequestError, ConflictError, NotFoundError } from '../../lib/errors.
 import { extractAuth } from '../../lib/auth.js';
 import * as repo from './repository.js';
 import * as coordinator from './coordinator.js';
+import * as artifactsBlob from './artifacts-blob.js';
 import {
   SubmitJobSchema,
   ListJobsQuerySchema,
@@ -29,6 +34,7 @@ import {
   RenewLeaseSchema,
   ReleaseLeaseSchema,
   HeartbeatSchema,
+  UploadArtifactSchema,
 } from './types.js';
 
 function badRequest(issues: { message: string }[]): never {
@@ -179,4 +185,53 @@ export async function fleetRoutes(app: FastifyInstance) {
     const events = await repo.listEvents(id);
     return { events };
   });
+
+  // ── Artifacts: upload (base64 body → blob + pointer) ──
+  app.post('/fleet/jobs/:id/artifacts', async (req, reply) => {
+    await extractAuth(req);
+    const { id: jobId } = req.params as { id: string };
+    const parsed = UploadArtifactSchema.safeParse(req.body);
+    if (!parsed.success) badRequest(parsed.error.issues);
+    const pid = parsed.data.productId || getRequestProductId(req);
+    const bytes = Buffer.from(parsed.data.contentBase64, 'base64');
+    if (bytes.length === 0) badRequest([{ message: 'contentBase64 decoded to empty bytes' }]);
+    const { artifact, downloadUrl } = await artifactsBlob.uploadArtifact({
+      productId: pid,
+      jobId,
+      kind: parsed.data.kind,
+      bytes,
+      contentType: parsed.data.contentType,
+      runId: parsed.data.runId,
+    });
+    reply.code(201);
+    return { artifact, downloadUrl };
+  });
+
+  // ── Artifacts: list a job's pointers ──
+  app.get('/fleet/jobs/:id/artifacts', async req => {
+    await extractAuth(req);
+    const { id: jobId } = req.params as { id: string };
+    const artifacts = await repo.listArtifactsByJob(jobId);
+    return { artifacts };
+  });
+
+  // ── Artifacts: pointer + fresh SAS download URL ──
+  app.get('/fleet/artifacts/:artifactId', async req => {
+    await extractAuth(req);
+    const { artifactId } = req.params as { artifactId: string };
+    const pid = getRequestProductId(req);
+    const found = await artifactsBlob.getArtifactDownload(artifactId, pid);
+    if (!found) throw new NotFoundError('Artifact not found');
+    return found;
+  });
+
+  // ── Artifacts: delete pointer (and backing blob) ──
+  app.delete('/fleet/artifacts/:artifactId', async req => {
+    await extractAuth(req);
+    const { artifactId } = req.params as { artifactId: string };
+    const pid = getRequestProductId(req);
+    const deleted = await artifactsBlob.deleteArtifact(artifactId, pid);
+    if (!deleted) throw new NotFoundError('Artifact not found');
+    return { deleted: true };
+  });
 }
diff --git a/services/platform-service/src/modules/fleet/types.test.ts b/services/platform-service/src/modules/fleet/types.test.ts
index 5cdb93ff..f944445f 100644
--- a/services/platform-service/src/modules/fleet/types.test.ts
+++ b/services/platform-service/src/modules/fleet/types.test.ts
@@ -160,18 +160,22 @@ describe('FleetProfileDocSchema / FleetEventDocSchema / FleetArtifactDocSchema',
     const { type: _t, ...bad } = valid;
     expect(FleetEventDocSchema.safeParse(bad).success).toBe(false);
   });
-  it('accepts a valid artifact and rejects missing blobUrl', () => {
+  it('accepts a valid artifact pointer and rejects missing blobKey', () => {
     const valid = {
       id: 'art_1',
       productId: 'lysnrai',
       jobId: 'fjob_1',
       kind: 'coverage',
-      blobUrl: 'https://b/x',
+      blobKey: 'fleet/lysnrai/fjob_1/art_1-coverage',
+      contentType: 'application/json',
+      sizeBytes: 1234,
       createdAt: now,
     };
     expect(FleetArtifactDocSchema.safeParse(valid).success).toBe(true);
-    const { blobUrl: _b, ...bad } = valid;
+    const { blobKey: _b, ...bad } = valid;
     expect(FleetArtifactDocSchema.safeParse(bad).success).toBe(false);
+    // kind is a closed enum — an unknown kind is rejected
+    expect(FleetArtifactDocSchema.safeParse({ ...valid, kind: 'bogus' }).success).toBe(false);
   });
 });
 
diff --git a/services/platform-service/src/modules/fleet/types.ts b/services/platform-service/src/modules/fleet/types.ts
index f20c859f..5cc13e4b 100644
--- a/services/platform-service/src/modules/fleet/types.ts
+++ b/services/platform-service/src/modules/fleet/types.ts
@@ -76,6 +76,10 @@ export type LeaseStatus = (typeof LEASE_STATUS)[number];
 export const JOB_KINDS = ['leaf', 'composite'] as const;
 export type JobKind = (typeof JOB_KINDS)[number];
 
+/** Artifact categories (§13/§26). Large outputs live in blob; Cosmos holds pointers only. */
+export const FLEET_ARTIFACT_KINDS = ['log', 'coverage', 'screenshot', 'build', 'other'] as const;
+export type FleetArtifactKind = (typeof FLEET_ARTIFACT_KINDS)[number];
+
 // ── Shared value objects ─────────────────────────────────────────────────────
 
 export const CheckpointSchema = z.object({
@@ -232,15 +236,25 @@ export const FleetEventDocSchema = z.object({
 });
 export type FleetEventDoc = z.infer<typeof FleetEventDocSchema>;
 
-/** FleetArtifactDoc — pointer to a blob-stored artifact (pk `/jobId`). No inline logs. */
+/**
+ * FleetArtifactDoc — a POINTER to a blob-stored run output (pk `/jobId`).
+ *
+ * Large outputs (logs, coverage, screenshots, build output) are written to blob
+ * storage; only this pointer (blob key + size/content-type/sha256 metadata) lives
+ * in Cosmos — NEVER the bytes themselves (doc-size + RU limits, §13). The
+ * short-lived SAS read URL is minted on demand from `blobKey` and is intentionally
+ * NOT persisted on the doc.
+ */
 export const FleetArtifactDocSchema = z.object({
   id: z.string(),
   productId: z.string().min(1),
   jobId: z.string().min(1),
   runId: z.string().optional(),
-  kind: z.string().min(1),
-  blobUrl: z.string().min(1),
-  sizeBytes: z.number().int().nonnegative().optional(),
+  kind: z.enum(FLEET_ARTIFACT_KINDS),
+  blobKey: z.string().min(1),
+  contentType: z.string().min(1),
+  sizeBytes: z.number().int().nonnegative(),
+  sha256: z.string().optional(),
   createdAt: z.string(),
 });
 export type FleetArtifactDoc = z.infer<typeof FleetArtifactDocSchema>;
@@ -315,3 +329,17 @@ export const HeartbeatSchema = z.object({
   seatLimit: z.number().int().positive().optional(),
 });
 export type HeartbeatInput = z.infer<typeof HeartbeatSchema>;
+
+/**
+ * Upload an artifact for a job. The bytes are carried base64-encoded in the JSON
+ * body (large content is offloaded to blob server-side; nothing is stored inline
+ * in Cosmos). `productId` may override the request-resolved product.
+ */
+export const UploadArtifactSchema = z.object({
+  productId: z.string().min(1).optional(),
+  runId: z.string().min(1).optional(),
+  kind: z.enum(FLEET_ARTIFACT_KINDS),
+  contentType: z.string().min(1).default('application/octet-stream'),
+  contentBase64: z.string().min(1),
+});
+export type UploadArtifactInput = z.infer<typeof UploadArtifactSchema>;