Function syncToolAvailability

packages/hosts/mcp/src/tool-server.ts:2291–2341

()

    // fires on the `notifications/initialized` notification, which is never
    // persisted. `appsSupported()` is what makes the restored case correct.
    const syncToolAvailability = () => {
      const clientCapabilities = server.server.getClientCapabilities();
      const uiCapability = getUiCapability(
        clientCapabilities as
          | (ClientCapabilities & { extensions?: Record<string, unknown> })
          | null,
      );
      // Absent capabilities (the SDK returns `undefined`) mean `initialize`
      // hasn't happened on THIS server instance — the construction-time call
      // below, or a cold restore that resumed mid-conversation. Neither is
      // evidence the client lost apps support, so the restored value stands
      // until a real `initialize` replaces it. Reading `false` off an absent
      // value here is exactly what made a cold-restored session fall back to
      // deep links.
      const negotiated = clientCapabilities
        ? Boolean(uiCapability?.mimeTypes?.includes(RESOURCE_MIME_TYPE))
        : appsEnabled;
      const changed = negotiated !== appsEnabled;
      applyAppsEnabled(negotiated);

      // Persist only a real negotiation that moved the value, so the next cold
      // restore seeds itself. Best-effort: the session must not fail on it.
      // The `clientCapabilities` guard matters beyond skipping a no-op write:
      // persisting an absent-capability reading would make a downgrade durable
      // for every future restore of the session.
      const onAppsEnabledChange = config.onAppsEnabledChange;
      if (clientCapabilities && changed && onAppsEnabledChange) {
        // oxlint-disable-next-line executor/no-effect-escape-hatch -- boundary: `oninitialized` is a sync SDK hook; persistence is fire-and-forget and its failure must not fail the session
        void Effect.runPromiseWith(context)(
          onAppsEnabledChange(negotiated).pipe(Effect.ignoreCause({ log: false })),
        );
      }

      console.error(
        "[executor] MCP session mode",
        JSON.stringify({
          ...capabilitySnapshot(server),
          elicitationMode: elicitationMode.mode,
          resumeEnabled: elicitationMode.mode !== "native",
        }),
      );
      debugLog("tool.visibility", {
        clientCapabilities: clientCapabilities ?? null,
        elicitationSupport: getElicitationSupport(server),
        elicitationMode: elicitationMode.mode,
        resumeEnabled: elicitationMode.mode !== "native",
        appsSupport: uiCapability ?? null,
        appsEnabled,
        executeActionEnabled: appsEnabled,
      });
    };

    yield* Effect.sync(() => {
      syncToolAvailability();