diff --git a/packages/opencode/src/command/index.ts b/packages/opencode/src/command/index.ts
index 96e171733df0..0c4db8f73ee1 100644
--- a/packages/opencode/src/command/index.ts
+++ b/packages/opencode/src/command/index.ts
@@ -35,6 +35,7 @@ export const Info = Schema.Struct({
   // Some command templates are lazy promises from MCP prompt resolution.
   template: Schema.Unknown,
   subtask: Schema.optional(Schema.Boolean),
+  noReply: Schema.optional(Schema.Boolean),
   hints: Schema.Array(Schema.String),
 }).annotate({ identifier: "Command" })
 
@@ -105,6 +106,7 @@ export const layer = Layer.effect(
             return command.template
           },
           subtask: command.subtask,
+          noReply: command.noReply,
           hints: hints(command.template),
         }
       }
diff --git a/packages/opencode/src/config/command.ts b/packages/opencode/src/config/command.ts
index d5046b6a1756..9fb16ed56794 100644
--- a/packages/opencode/src/config/command.ts
+++ b/packages/opencode/src/config/command.ts
@@ -17,6 +17,7 @@ export const Info = Schema.Struct({
   agent: Schema.optional(Schema.String),
   model: Schema.optional(ConfigModelID),
   subtask: Schema.optional(Schema.Boolean),
+  noReply: Schema.optional(Schema.Boolean),
 })
 
 export type Info = Schema.Schema.Type<typeof Info>
diff --git a/packages/opencode/src/session/prompt.ts b/packages/opencode/src/session/prompt.ts
index fc9fa0b96a8c..9e13816a3c64 100644
--- a/packages/opencode/src/session/prompt.ts
+++ b/packages/opencode/src/session/prompt.ts
@@ -1224,7 +1224,35 @@ export const layer = Layer.effect(
         yield* sessions.setPermission({ sessionID: session.id, permission: permissions })
       }
 
-      if (input.noReply === true) return message
+      if (input.noReply === true) {
+        const ctx = yield* InstanceState.context
+        const assistantMsg: MessageV2.Assistant = {
+          id: MessageID.ascending(),
+          parentID: message.info.id,
+          role: "assistant",
+          mode: message.info.agent,
+          agent: message.info.agent,
+          variant: message.info.model.variant,
+          path: { cwd: ctx.directory, root: ctx.worktree },
+          cost: 0,
+          tokens: { input: 0, output: 0, reasoning: 0, cache: { read: 0, write: 0 } },
+          modelID: message.info.model.modelID,
+          providerID: message.info.model.providerID,
+          time: { created: Date.now(), completed: Date.now() },
+          sessionID: input.sessionID,
+        }
+        yield* sessions.updateMessage(assistantMsg)
+
+        for (const part of input.parts) {
+          yield* sessions.updatePart({
+            ...part,
+            id: PartID.ascending(),
+            messageID: assistantMsg.id,
+            sessionID: input.sessionID,
+          } as MessageV2.Part)
+        }
+        return message
+      }
       return yield* loop({ sessionID: input.sessionID })
     })
 
@@ -1601,6 +1629,7 @@ export const layer = Layer.effect(
         agent: userAgent,
         parts,
         variant: input.variant,
+        noReply: cmd.noReply ?? false,
       })
       yield* bus.publish(Command.Event.Executed, {
         name: input.command,
diff --git a/packages/opencode/test/session/prompt.test.ts b/packages/opencode/test/session/prompt.test.ts
index ff9ded4d1927..5a08bd22143b 100644
--- a/packages/opencode/test/session/prompt.test.ts
+++ b/packages/opencode/test/session/prompt.test.ts
@@ -2314,3 +2314,48 @@ noLLMServer.instance(
     }),
   30_000,
 )
+
+// noReply command semantics
+
+noLLMServer.instance(
+  "noReply command skips LLM and creates assistant message with parts",
+  () =>
+    Effect.gen(function* () {
+      const prompt = yield* SessionPrompt.Service
+      const sessions = yield* Session.Service
+      const session = yield* sessions.create({})
+
+      const result = yield* prompt.command({
+        sessionID: session.id,
+        command: "noreply-test",
+        arguments: "hello",
+      })
+
+      // command() returns the user message
+      expect(result.info.role).toBe("user")
+
+      // check that an assistant message was created with the template text
+      const messages = yield* sessions.messages({ sessionID: session.id })
+      const assistants = messages.filter((msg) => msg.info.role === "assistant")
+      expect(assistants.length).toBe(1)
+      const assistant = assistants[0]
+      expect(assistant.info.role).toBe("assistant")
+      if (assistant.info.role === "assistant") {
+        expect(assistant.info.time.completed).toBeDefined()
+      }
+      const textParts = assistant.parts.filter((p) => p.type === "text")
+      expect(textParts.length).toBeGreaterThan(0)
+      expect(textParts.some((p) => p.type === "text" && p.text.includes("hello"))).toBe(true)
+    }),
+  {
+    config: {
+      ...cfg,
+      command: {
+        "noreply-test": {
+          template: "NoReply test: $ARGUMENTS",
+          noReply: true,
+        },
+      },
+    },
+  },
+)