diff --git a/packages/client/src/promise/generated/client.ts b/packages/client/src/promise/generated/client.ts
index d29a5268579..cb45acafb89 100644
--- a/packages/client/src/promise/generated/client.ts
+++ b/packages/client/src/promise/generated/client.ts
@@ -492,7 +492,7 @@ export function make(options: ClientOptions) {
             path: `/api/agent`,
             query: { location: input?.["location"] },
             successStatus: 200,
-            declaredStatuses: [400, 401, 404],
+            declaredStatuses: [400, 401, 404, 503],
             empty: false,
           },
           requestOptions,
diff --git a/packages/protocol/openapi.json b/packages/protocol/openapi.json
index ec858694639..48964f54d3e 100644
--- a/packages/protocol/openapi.json
+++ b/packages/protocol/openapi.json
@@ -359,6 +359,16 @@
                 }
               }
             }
+          },
+          "503": {
+            "description": "ServiceUnavailableError",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ServiceUnavailableErrorEncoded"
+                }
+              }
+            }
           }
         },
         "description": "Retrieve currently registered agents.",
diff --git a/packages/protocol/src/groups/agent.ts b/packages/protocol/src/groups/agent.ts
index 485d0ae37cb..eecf67af085 100644
--- a/packages/protocol/src/groups/agent.ts
+++ b/packages/protocol/src/groups/agent.ts
@@ -3,13 +3,14 @@ import { Location } from "@opencode/schema/location"
 import { Schema } from "effect"
 import { HttpApiEndpoint, HttpApiGroup, OpenApi } from "effect/http-api"
 import { LocationQuery, locationQueryOpenApi } from "./location.js"
-import { AgentNotFoundError } from "../errors.js"
+import { AgentNotFoundError, ServiceUnavailableError } from "../errors.js"
 
 export const AgentGroup = HttpApiGroup.make("server.agent")
   .add(
     HttpApiEndpoint.get("agent.list", "/api/agent", {
       query: LocationQuery,
       success: Location.response(Schema.Array(Agent.Info)),
+      error: ServiceUnavailableError,
     })
       .annotateMerge(locationQueryOpenApi)
       .annotateMerge(
diff --git a/packages/server/src/handlers/agent.ts b/packages/server/src/handlers/agent.ts
index f54148af226..eff3bb9497a 100644
--- a/packages/server/src/handlers/agent.ts
+++ b/packages/server/src/handlers/agent.ts
@@ -2,13 +2,14 @@ import { Agent } from "@opencode/core/agent"
 import { Effect } from "effect"
 import { HttpApiBuilder } from "effect/http-api"
 import { Api } from "../api"
-import { response } from "../location"
+import { awaitPlugins, response } from "../location"
 import { AgentNotFoundError } from "@opencode/protocol/errors"
 
 export const AgentHandler = HttpApiBuilder.group(Api, "server.agent", (handlers) =>
   handlers
     .handle("agent.list", () =>
       Effect.gen(function* () {
+        yield* awaitPlugins
         return yield* response(Agent.Service.use((agent) => agent.list()))
       }),
     )
diff --git a/packages/server/src/handlers/provider.ts b/packages/server/src/handlers/provider.ts
index ab9c2201a5e..3b0bdf4a495 100644
--- a/packages/server/src/handlers/provider.ts
+++ b/packages/server/src/handlers/provider.ts
@@ -3,7 +3,7 @@ import { ProviderNotFoundError } from "@opencode/protocol/errors"
 import { Effect } from "effect"
 import { HttpApiBuilder } from "effect/http-api"
 import { Api } from "../api"
-import { response } from "../location"
+import { awaitPlugins, response } from "../location"
 
 export const ProviderHandler = HttpApiBuilder.group(Api, "server.provider", (handlers) =>
   Effect.gen(function* () {
@@ -11,6 +11,7 @@ export const ProviderHandler = HttpApiBuilder.group(Api, "server.provider", (han
       .handle(
         "provider.list",
         Effect.fn(function* () {
+          yield* awaitPlugins
           const providers = yield* Provider.Service
           return yield* response(providers.available())
         }),
diff --git a/packages/server/test/provider.test.ts b/packages/server/test/provider.test.ts
index 9da592289ee..4e132e7fd45 100644
--- a/packages/server/test/provider.test.ts
+++ b/packages/server/test/provider.test.ts
@@ -8,7 +8,7 @@ import { it } from "../../core/test/lib/effect"
 import { createRoutes } from "../src/routes"
 
 it.live(
-  "provider reads stay nonblocking while authentication discovery waits for plugins",
+  "agent and provider lists wait for plugins while single provider reads stay nonblocking",
   () =>
     Effect.gen(function* () {
       const tmp = yield* tmpdirScoped("opencode-provider-endpoints-")
@@ -32,6 +32,7 @@ it.live(
                   models: { chat: {} },
                 },
               },
+              agents: { reviewer: { description: "Reviews changes" } },
             }),
           },
         }).pipe(Layer.provide(HttpServer.layerServices)),
@@ -62,22 +63,35 @@ it.live(
             }),
           )
         })
-      // Config providers activate after SDK plugins; reads must return the current snapshot without waiting.
-      const list = yield* request("GET", "/api/provider").pipe(Effect.timeout("2 seconds"))
+      // Config providers and agents activate after SDK plugins, so the lists wait rather than answer with a partial
+      // catalog that a client would cache as loaded.
+      const providers = yield* request("GET", "/api/provider").pipe(Effect.forkScoped)
+      const agents = yield* request("GET", "/api/agent").pipe(Effect.forkScoped)
       yield* Deferred.await(started)
       const integrations = yield* request("GET", "/api/integration").pipe(Effect.forkScoped)
-      expect(list.status).toBe(200)
-      expect(yield* Effect.promise(() => list.json())).toMatchObject({
-        location: { directory: tmp.path },
-        data: expect.not.arrayContaining([expect.objectContaining({ id: "custom" })]),
-      })
       const get = yield* request("GET", "/api/provider/custom").pipe(Effect.timeout("2 seconds"))
       expect(get.status).toBe(404)
       expect(yield* Effect.promise(() => get.json())).toMatchObject({
         _tag: "ProviderNotFoundError",
         providerID: "custom",
       })
+      expect(providers.pollUnsafe()).toBeUndefined()
+      expect(agents.pollUnsafe()).toBeUndefined()
       yield* Deferred.succeed(release, undefined)
+      const list = yield* Fiber.join(providers)
+      expect(list.status).toBe(200)
+      expect(yield* Effect.promise(() => list.json())).toMatchObject({
+        location: { directory: tmp.path },
+        data: expect.arrayContaining([expect.objectContaining({ id: "custom" })]),
+      })
+      const agentList = yield* Fiber.join(agents)
+      expect(agentList.status).toBe(200)
+      expect(yield* Effect.promise(() => agentList.json())).toMatchObject({
+        data: expect.arrayContaining([
+          expect.objectContaining({ id: "build" }),
+          expect.objectContaining({ id: "reviewer" }),
+        ]),
+      })
       const discovered = yield* Fiber.join(integrations)
       expect(discovered.status).toBe(200)
       expect(yield* Effect.promise(() => discovered.json())).toMatchObject({