diff --git a/packages/core/src/codemode/tool.ts b/packages/core/src/codemode/tool.ts
index 224d097a2af..e3907a8163b 100644
--- a/packages/core/src/codemode/tool.ts
+++ b/packages/core/src/codemode/tool.ts
@@ -1,9 +1,9 @@
 export * as CodeModeTool from "./tool.js"
 
-import { CodeMode, Tool, toolError } from "@opencode-ai/codemode"
+import { CodeMode, Namespace, Tool, toolError } from "@opencode-ai/codemode"
 import type { Content, Context, Error, Info, Metadata, Result } from "@opencode-ai/schema/tool"
 import { Effect, Ref, Schema, Semaphore } from "effect"
-import { definition, normalizedName } from "../tool/runtime.js"
+import { definition, namespace, normalizedName } from "../tool/runtime.js"
 
 const ExecuteFile = Schema.Struct({
   data: Schema.String,
@@ -148,7 +148,8 @@ function runtime(
   executeTool: (name: string, tool: Info, input: unknown) => Effect.Effect<unknown, unknown>,
   hooks?: CodeMode.ToolCallHooks,
 ) {
-  const tools: Record<string, Tool.Tool<never>> = {}
+  const tools: Record<string, Tool.Tool<never> | Namespace.Namespace<never>> = {}
+  const namespaces = new Map<string, string>()
   for (const [name, registration] of registrations) {
     const child = definition(registration)
     const path = qualifiedName(registration)
@@ -158,14 +159,19 @@ function runtime(
       output: child.outputSchema ?? Schema.NullOr(Schema.String),
       execute: (input) => executeTool(name, registration, input),
     })
+    const group = namespace(registration)
+    if (group?.description !== undefined) namespaces.set(group.name, group.description)
   }
+  for (const [name, description] of namespaces)
+    if (!Object.hasOwn(tools, name)) tools[name] = Namespace.make({ description, tools: {} })
   return CodeMode.make<typeof tools>({ tools, ...hooks })
 }
 
 function qualifiedName(registration: Info) {
   const normalized = normalizedName(registration)
-  if (registration.options?.namespace === undefined) return normalized
-  return `${registration.options.namespace}.${normalized}`
+  const group = namespace(registration)
+  if (group === undefined) return normalized
+  return `${group.name}.${normalized}`
 }
 
 // Tool inputs arrive as parsed JSON, so the JSON value cast is a boundary fact.
diff --git a/packages/core/src/tool.ts b/packages/core/src/tool.ts
index d1dc8c581fd..e9c4d4dac4b 100644
--- a/packages/core/src/tool.ts
+++ b/packages/core/src/tool.ts
@@ -15,7 +15,7 @@ import { PluginHooks } from "./plugin/hooks.js"
 import { SessionMessage } from "./session/message.js"
 import { SessionSchema } from "./session/schema.js"
 import { State } from "./state.js"
-import { definition, effectiveName, execute, normalizedName, normalizeContent } from "./tool/runtime.js"
+import { definition, effectiveName, execute, namespace, normalizedName, normalizeContent } from "./tool/runtime.js"
 import { Wildcard } from "./util/wildcard.js"
 
 export class RegistrationError extends Schema.TaggedError<RegistrationError>()("Tool.RegistrationError", {
@@ -191,7 +191,7 @@ const layer = Layer.effect(
           ({ tool, error }) =>
             Effect.logError("Skipping invalid tool registration", {
               name: tool.name,
-              namespace: tool.options?.namespace,
+              namespace: namespace(tool)?.name,
               error: error.message,
             }),
           { discard: true },
@@ -268,9 +268,12 @@ function schemaMakeError(error: unknown) {
 }
 
 function registrationError(tool: Tool.Info) {
-  const namespace = tool.options?.namespace
-  if (namespace !== undefined && !namespace.split(".").every((segment) => /^[A-Za-z0-9_-]{1,64}$/.test(segment)))
-    return new RegistrationError({ name: namespace, message: `Invalid tool namespace: ${JSON.stringify(namespace)}` })
+  const group = namespace(tool)
+  if (group !== undefined && !group.name.split(".").every((segment) => /^[A-Za-z0-9_-]{1,64}$/.test(segment)))
+    return new RegistrationError({
+      name: group.name,
+      message: `Invalid tool namespace: ${JSON.stringify(group.name)}`,
+    })
   const name = normalizedName(tool)
   if (!/^[A-Za-z0-9_-]{1,64}$/.test(name)) return new RegistrationError({ name, message: `Invalid tool name: ${name}` })
   const id = effectiveName(tool)
diff --git a/packages/core/src/tool/runtime.ts b/packages/core/src/tool/runtime.ts
index b56d488db03..d8af70174a8 100644
--- a/packages/core/src/tool/runtime.ts
+++ b/packages/core/src/tool/runtime.ts
@@ -272,7 +272,14 @@ const stringify = (value: unknown) => {
 
 export const normalizedName = (tool: Tool.Info) => tool.name.replace(/[^a-zA-Z0-9_-]/g, "_")
 
-export const effectiveName = (tool: Tool.Info) =>
-  tool.options?.namespace === undefined
-    ? normalizedName(tool)
-    : `${tool.options.namespace.replaceAll(".", "_")}_${normalizedName(tool)}`
+export const namespace = (tool: Tool.Info) => {
+  const value = tool.options?.namespace
+  if (value === undefined) return
+  return typeof value === "string" ? { name: value } : value
+}
+
+export const effectiveName = (tool: Tool.Info) => {
+  const group = namespace(tool)
+  if (group === undefined) return normalizedName(tool)
+  return `${group.name.replaceAll(".", "_")}_${normalizedName(tool)}`
+}
diff --git a/packages/core/test/tool-registry.test.ts b/packages/core/test/tool-registry.test.ts
index b38826585c1..974cc140263 100644
--- a/packages/core/test/tool-registry.test.ts
+++ b/packages/core/test/tool-registry.test.ts
@@ -536,6 +536,7 @@ describe("Tool", () => {
       yield* service.transform((draft) => {
         draft.add({ ...make(), name: "first", options: { codemode: false } })
         draft.add({ ...make(), name: "second", options: { namespace: "invalid..namespace", codemode: false } })
+        draft.add({ ...make(), name: "third", options: { namespace: { name: "also..invalid" } } })
         draft.add({ ...make(), name: "second", options: { namespace: "invalid__namespace" } })
       })
 
@@ -545,6 +546,40 @@ describe("Tool", () => {
     }),
   )
 
+  it.effect("supports described namespaces without changing string namespace behavior", () =>
+    Effect.gen(function* () {
+      const service = yield* Tool.Service
+      yield* service.transform((draft) => {
+        draft.add({ ...make(), name: "plain", options: { namespace: "legacy" } })
+        draft.add({
+          ...make(),
+          name: "direct",
+          options: { namespace: { name: "registry", description: "Package tools" }, codemode: false },
+        })
+        draft.add({
+          ...make(),
+          name: "search",
+          description: "Search packages",
+          options: { namespace: { name: "registry", description: "Package publishing and discovery" } },
+        })
+      })
+
+      const snapshot = yield* service.snapshot()
+      expect(snapshot.definitions.map((tool) => tool.name)).toEqual(["registry_direct", "execute"])
+      expect(snapshot.codeModeCatalog?.map((tool) => tool.path)).toEqual(["legacy.plain", "registry.search"])
+      const result = yield* snapshot.execute({
+        ...call("execute"),
+        call: {
+          type: "tool-call",
+          id: "namespace-search",
+          name: "execute",
+          input: { code: 'return search({ query: "publishing discovery" })' },
+        },
+      })
+      expect(result.output).toMatchObject({ output: expect.stringContaining("tools.registry.search") })
+    }),
+  )
+
   it.effect("logs invalid tool definitions without dropping healthy tools", () => {
     const output: unknown[] = []
     const logger = Logger.map(Logger.formatStructured, (entry) => {
diff --git a/packages/schema/src/tool.ts b/packages/schema/src/tool.ts
index 7f87dccb9ba..d63d2c9c131 100644
--- a/packages/schema/src/tool.ts
+++ b/packages/schema/src/tool.ts
@@ -20,10 +20,15 @@ export interface Context {
 }
 
 interface BaseOptions {
-  readonly namespace?: string
+  readonly namespace?: string | Namespace
   readonly permission?: string
 }
 
+export interface Namespace {
+  readonly name: string
+  readonly description?: string
+}
+
 export type Options = BaseOptions &
   (
     | {
diff --git a/packages/www/src/docs/content/build/plugins/effect.mdx b/packages/www/src/docs/content/build/plugins/effect.mdx
index 6b902c3fafd..c0ee2dbf93a 100644
--- a/packages/www/src/docs/content/build/plugins/effect.mdx
+++ b/packages/www/src/docs/content/build/plugins/effect.mdx
@@ -843,7 +843,10 @@ effect: (ctx) =>
         description: "Create a greeting",
         input: Schema.Struct({ name: Schema.String }),
         output: Schema.Struct({ greeting: Schema.String }),
-        options: { namespace: "acme", codemode: true },
+        options: {
+          namespace: { name: "acme", description: "Customer account tools" },
+          codemode: true,
+        },
         execute: ({ name }, context) =>
           Effect.gen(function* () {
             yield* context.progress({ status: "greeting" })
@@ -854,6 +857,9 @@ effect: (ctx) =>
   }),
 ```
 
+Use a namespace object to add model-visible search context for its CodeMode tools. A string such as
+`namespace: "acme"` remains supported when no namespace description is needed.
+
 Call `yield* ctx.tool.reload()` after changing source data captured by the callback. Reload replays active transforms
 without changing their order; it does not rerun the plugin effect.
 
diff --git a/packages/www/src/docs/content/build/plugins/index.mdx b/packages/www/src/docs/content/build/plugins/index.mdx
index 7fbf7cce9c2..0ef1b575ebd 100644
--- a/packages/www/src/docs/content/build/plugins/index.mdx
+++ b/packages/www/src/docs/content/build/plugins/index.mdx
@@ -808,7 +808,10 @@ const registration = await ctx.tool.transform((draft) => {
       required: ["name"],
       additionalProperties: false,
     },
-    options: { namespace: "acme", codemode: true },
+    options: {
+      namespace: { name: "acme", description: "Customer account tools" },
+      codemode: true,
+    },
     execute: async (input, tool) => {
       await tool.progress({ status: "greeting" })
       return { content: `Hello ${(input as { name: string }).name}!` }
@@ -824,6 +827,9 @@ changing their order; it does not rerun plugin setup.
 await ctx.tool.reload()
 ```
 
+Use a namespace object to add model-visible search context for its CodeMode tools. A string such as
+`namespace: "acme"` remains supported when no namespace description is needed.
+
 Use `list()` and `get()` to inspect tools currently in the draft. Tools have an `id` containing their effective name,
 and `get()` returns `undefined` when that ID is not present. Use `update` and `remove` with the effective tool name,
 including its namespace (`acme_greeting` above). Dots in