fix(server): Address premature provider reaping by treating provider runtime output as session activity

apps/server/src/persistence/ProviderSessionRuntime.ts

@@ -56,6 +56,12 @@ export type GetProviderSessionRuntimeInput = typeof GetProviderSessionRuntimeInp
 export const DeleteProviderSessionRuntimeInput = Schema.Struct({ threadId: ThreadId });
 export type DeleteProviderSessionRuntimeInput = typeof DeleteProviderSessionRuntimeInput.Type;
 
+export const TouchProviderSessionRuntimeInput = Schema.Struct({
+  threadId: ThreadId,
+  lastSeenAt: IsoDateTime,
+});
+export type TouchProviderSessionRuntimeInput = typeof TouchProviderSessionRuntimeInput.Type;
+
 /**
  * ProviderSessionRuntimeRepository - Service tag for provider runtime persistence.
  */
@@ -97,6 +103,16 @@ export class ProviderSessionRuntimeRepository extends Context.Service<
     readonly deleteByThreadId: (
       input: DeleteProviderSessionRuntimeInput,
     ) => Effect.Effect<void, ProviderSessionRuntimeRepositoryError>;
+
+    /**
+     * Bump `last_seen_at` for an existing runtime row.
+     *
+     * No-op when no row matches. Cheaper than `upsert` for high-frequency
+     * activity signals because it skips the SELECT and JSON re-encoding.
+     */
+    readonly touchByThreadId: (
+      input: TouchProviderSessionRuntimeInput,
+    ) => Effect.Effect<void, ProviderSessionRuntimeRepositoryError>;
   }
 >()("t3/persistence/ProviderSessionRuntime/ProviderSessionRuntimeRepository") {}
 
@@ -233,6 +249,16 @@ export const make = Effect.gen(function* () {
       `,
   });
 
+  const touchRuntimeByThreadId = SqlSchema.void({
+    Request: TouchProviderSessionRuntimeInput,
+    execute: ({ threadId, lastSeenAt }) =>
+      sql`
+        UPDATE provider_session_runtime
+        SET last_seen_at = ${lastSeenAt}
+        WHERE thread_id = ${threadId}
+      `,
+  });
+
   const upsert: ProviderSessionRuntimeRepository["Service"]["upsert"] = (runtime) =>
     upsertRuntimeRow(runtime).pipe(
       Effect.mapError(
@@ -308,11 +334,23 @@ export const make = Effect.gen(function* () {
       ),
     );
 
+  const touchByThreadId: ProviderSessionRuntimeRepository["Service"]["touchByThreadId"] = (input) =>
+    touchRuntimeByThreadId(input).pipe(
+      Effect.mapError(
+        toPersistenceSqlOrDecodeError(
+          "ProviderSessionRuntimeRepository.touchByThreadId:query",
+          "ProviderSessionRuntimeRepository.touchByThreadId:encodeRequest",
+          { threadId: input.threadId },
+        ),
+      ),
+    );
+
   return {
     upsert,
     getByThreadId,
     list,
     deleteByThreadId,
+    touchByThreadId,
   } satisfies ProviderSessionRuntimeRepository["Service"];
 });
 

apps/server/src/provider/Layers/CodexAdapter.test.ts

@@ -213,6 +213,7 @@ function makeScopedRuntimeFactory(options?: { readonly failConstruction?: boolea
 
 const providerSessionDirectoryTestLayer = Layer.succeed(ProviderSessionDirectory, {
   upsert: () => Effect.void,
+  touch: () => Effect.void,
   getProvider: () =>
     Effect.die(new Error("ProviderSessionDirectory.getProvider is not used in test")),
   getBinding: () => Effect.succeed(Option.none()),

apps/server/src/provider/Layers/OpenCodeAdapter.test.ts

@@ -180,6 +180,7 @@ const OpenCodeRuntimeTestDouble: OpenCodeRuntimeShape = {
 
 const providerSessionDirectoryTestLayer = Layer.succeed(ProviderSessionDirectory, {
   upsert: () => Effect.void,
+  touch: () => Effect.void,
   getProvider: () =>
     Effect.die(new Error("ProviderSessionDirectory.getProvider is not used in test")),
   getBinding: () => Effect.succeed(Option.none()),

apps/server/src/provider/Layers/ProviderService.ts

@@ -25,6 +25,7 @@ import {
   type ProviderSession,
 } from "@t3tools/contracts";
 import { causeErrorTag } from "@t3tools/shared/observability";
+import * as Cause from "effect/Cause";
 import * as DateTime from "effect/DateTime";
 import * as Effect from "effect/Effect";
 import * as Layer from "effect/Layer";
@@ -281,6 +282,30 @@ const makeProviderService = Effect.fn("makeProviderService")(function* (
       });
     });
 
+  // Runtime event types that must NOT count as session activity.
+  // `session.exited` means the provider process is gone — bumping `lastSeenAt`
+  // would keep the directory binding alive past the runtime that backs it,
+  // defeating the reaper. Extend this set if new event types turn out to fire
+  // after a session is effectively dead.
+  const SESSION_ACTIVITY_DENY_LIST: ReadonlySet<ProviderRuntimeEvent["type"]> = new Set([
+    "session.exited",
+  ]);
+
+  const bumpSessionActivity = (event: ProviderRuntimeEvent): Effect.Effect<void> =>
+    SESSION_ACTIVITY_DENY_LIST.has(event.type)
+      ? Effect.void
+      : directory.touch(event.threadId).pipe(
+          Effect.catchCause((cause) =>
+            Cause.hasInterruptsOnly(cause)
+              ? Effect.interrupt
+              : Effect.logDebug("provider.session.activity.touch-failed", {
+                  threadId: event.threadId,
+                  eventType: event.type,
+                  cause,
+                }),
+          ),
+        );
+
   const processRuntimeEvent = (
     source: {
       readonly instanceId: ProviderInstanceId;
@@ -293,7 +318,10 @@ const makeProviderService = Effect.fn("makeProviderService")(function* (
         increment(providerRuntimeEventsTotal, {
           provider: canonicalEvent.provider,
           eventType: canonicalEvent.type,
-        }).pipe(Effect.andThen(publishRuntimeEvent(canonicalEvent))),
+        }).pipe(
+          Effect.andThen(publishRuntimeEvent(canonicalEvent)),
+          Effect.andThen(bumpSessionActivity(canonicalEvent)),
+        ),
       ),
     );
 

apps/server/src/provider/Layers/ProviderSessionDirectory.ts

@@ -148,6 +148,13 @@ const makeProviderSessionDirectory = Effect.gen(function* () {
       .pipe(Effect.mapError(toPersistenceError("ProviderSessionDirectory.upsert:upsert")));
   });
 
+  const touch: ProviderSessionDirectoryShape["touch"] = Effect.fn(function* (threadId) {
+    const now = DateTime.formatIso(yield* DateTime.now);
+    yield* repository
+      .touchByThreadId({ threadId, lastSeenAt: now })
+      .pipe(Effect.mapError(toPersistenceError("ProviderSessionDirectory.touch:touchByThreadId")));
+  });
+
   const getProvider: ProviderSessionDirectoryShape["getProvider"] = (threadId) =>
     getBinding(threadId).pipe(
       Effect.flatMap((binding) =>
@@ -184,6 +191,7 @@ const makeProviderSessionDirectory = Effect.gen(function* () {
 
   return {
     upsert,
+    touch,
     getProvider,
     getBinding,
     listThreadIds,

apps/server/src/provider/Services/ProviderSessionDirectory.ts

@@ -45,6 +45,10 @@ export interface ProviderSessionDirectoryShape {
     binding: ProviderRuntimeBinding,
   ) => Effect.Effect<void, ProviderSessionDirectoryWriteError>;
 
+  readonly touch: (
+    threadId: ThreadId,
+  ) => Effect.Effect<void, ProviderSessionDirectoryPersistenceError>;
+
   readonly getProvider: (
     threadId: ThreadId,
   ) => Effect.Effect<ProviderDriverKind, ProviderSessionDirectoryReadError>;