diff --git a/backend/deploy/e2e/docker-compose.e2e.yml b/backend/deploy/e2e/docker-compose.e2e.yml
index ceb617b3a..cedfa2af7 100644
--- a/backend/deploy/e2e/docker-compose.e2e.yml
+++ b/backend/deploy/e2e/docker-compose.e2e.yml
@@ -37,6 +37,8 @@ services:
       # smoke stack must model. The images prepare these dirs with app ownership; a real deployment mounts volumes at them.
       Artifacts__StoreDirectory: /var/lib/codespace/artifacts
       Agents__RunSpoolDirectory: /var/lib/codespace/spool
+    volumes:
+      - artifacts:/var/lib/codespace/artifacts
     ports:
       - "18080:8080"
 
@@ -62,5 +64,9 @@ services:
       CODESPACE_CODEX_CLI_PATH: "/opt/fake-codex"
     volumes:
       - ./fake-codex:/opt/fake-codex:ro
+      - artifacts:/var/lib/codespace/artifacts
     ports:
       - "18081:8080"
+
+volumes:
+  artifacts:
diff --git a/backend/deploy/e2e/run.sh b/backend/deploy/e2e/run.sh
index cfc917053..12035883b 100755
--- a/backend/deploy/e2e/run.sh
+++ b/backend/deploy/e2e/run.sh
@@ -43,6 +43,18 @@ echo "==> health probe: worker"
 wait_ready "$WORKER" "worker"
 [ "$(curl -fsS -o /dev/null -w '%{http_code}' "$API/health/live" 2>/dev/null)" = "200" ] || fail "/health/live not 200 (anonymous liveness)"
 
+# A matching path string is not shared storage. Prove the actual production topology invariant through the running
+# roles: bytes created by the worker must be immediately readable by the API, and the named volume survives each
+# container's independent filesystem lifecycle. This catches the split-brain that leaves durable DB metadata pointing
+# at a blob that only ever existed inside one worker image layer.
+echo "==> artifact root is physically shared between worker and API"
+ARTIFACT_PROBE="cross-role-$(date +%s)-$$"
+$COMPOSE exec -T worker sh -c "printf '%s' '$ARTIFACT_PROBE' > /var/lib/codespace/artifacts/.cross-role-probe" || fail "worker could not write artifact probe"
+READBACK="$($COMPOSE exec -T api sh -c 'cat /var/lib/codespace/artifacts/.cross-role-probe')" || fail "API could not read worker artifact probe"
+[ "$READBACK" = "$ARTIFACT_PROBE" ] || fail "artifact probe readback mismatch"
+$COMPOSE exec -T api rm -f /var/lib/codespace/artifacts/.cross-role-probe || fail "API could not clean artifact probe"
+echo "    worker write → API read succeeded on the shared artifact volume"
+
 # The API image carries no agent-EXECUTION machinery. git is the ONE sanctioned exception, documented in
 # Dockerfile.api's header (S1): TaskLaunchService resolves a launch's immutable base vector synchronously via
 # `git ls-remote` (RemoteTipResolver) — read-only, no clone, no working tree. This check forbade it anyway and had
diff --git a/docker-compose.yml b/docker-compose.yml
index cd53bece3..7c567f908 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -74,6 +74,10 @@ services:
       # Stated explicitly rather than inheriting appsettings.json's committed dev key — a Production-labelled pod
       # silently signing tokens with a source-controlled key is exactly the footgun this line makes visible.
       Authentication__Jwt__SymmetricKey: "${CODESPACE_JWT_SYMMETRIC_KEY:-local-dev-only-jwt-key-minimum-32-chars-long}"
+    volumes:
+      # Artifact metadata lives in Postgres, but offloaded bytes must be visible to both roles. An image-layer path
+      # has the same spelling in each container while still being a different filesystem, and disappears on recreate.
+      - codespace-artifacts:/var/lib/codespace/artifacts
 
   # WORKER = THE LOCAL SANDBOX RUNNER — the Hangfire PROCESSING pod (HangfireHosting=Worker, which is also the
   # default when the key is absent). Agent runs + the per-run MCP endpoint execute HERE; the harness CLI is spawned as a confined child
@@ -120,6 +124,9 @@ services:
       CODESPACE_MCP_PROXY_PATH: "${CODESPACE_MCP_PROXY_PATH:-}"
       # Prod (userns-capable pod) arms the fail-closed isolation guard; left off for local dev (see comment above).
       # Sandbox__RequireConfinement: "true"
+    volumes:
+      - codespace-artifacts:/var/lib/codespace/artifacts
 
 volumes:
   codespace-pgdata:
+  codespace-artifacts: