diff --git a/packages/mcp-v2/src/tools/agents/run.ts b/packages/mcp-v2/src/tools/agents/run.ts
new file mode 100644
index 00000000000..4ee1b558d30
--- /dev/null
+++ b/packages/mcp-v2/src/tools/agents/run.ts
@@ -0,0 +1,66 @@
+import type { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
+import { z } from "zod";
+import { createMcpCaller } from "../../caller";
+import { defineTool } from "../../define-tool";
+import { hostServiceMutation } from "../../host-service-client";
+
+export function register(server: McpServer): void {
+	defineTool(server, {
+		name: "agents_run",
+		description:
+			"Launch an agent inside an existing workspace. Resolves the host that owns the workspace, then runs the named agent preset (or HostAgentConfig instance) with the given prompt in a fresh terminal session. Use this to start a second agent in a workspace that already exists; for create-and-spawn in a single call, pass `agents` to workspaces_create instead.",
+		inputSchema: {
+			workspaceId: z
+				.string()
+				.uuid()
+				.describe("Workspace UUID to run the agent in."),
+			agent: z
+				.string()
+				.min(1)
+				.describe(
+					"Agent preset id (e.g. `claude`, `codex`) or HostAgentConfig instance UUID.",
+				),
+			prompt: z.string().min(1).describe("Prompt sent to the agent."),
+			attachmentIds: z
+				.array(z.string().uuid())
+				.optional()
+				.describe(
+					"Host-scoped attachment UUIDs. The host resolves these to absolute paths and appends them to the prompt.",
+				),
+		},
+		handler: async (input, ctx) => {
+			const caller = createMcpCaller(ctx);
+			const workspace = await caller.v2Workspace.getFromHost({
+				organizationId: ctx.organizationId,
+				id: input.workspaceId,
+			});
+			if (!workspace) {
+				throw new Error(`Workspace not found: ${input.workspaceId}`);
+			}
+
+			return hostServiceMutation<
+				{
+					workspaceId: string;
+					agent: string;
+					prompt: string;
+					attachmentIds?: string[];
+				},
+				{ sessionId: string; label: string }
+			>(
+				{
+					relayUrl: ctx.relayUrl,
+					organizationId: ctx.organizationId,
+					hostId: workspace.hostId,
+					jwt: ctx.bearerToken,
+				},
+				"agents.run",
+				{
+					workspaceId: input.workspaceId,
+					agent: input.agent,
+					prompt: input.prompt,
+					attachmentIds: input.attachmentIds,
+				},
+			);
+		},
+	});
+}
diff --git a/packages/mcp-v2/src/tools/register.ts b/packages/mcp-v2/src/tools/register.ts
index 3b0dd7a76af..bcc8ec0bf58 100644
--- a/packages/mcp-v2/src/tools/register.ts
+++ b/packages/mcp-v2/src/tools/register.ts
@@ -4,6 +4,7 @@ import {
 	setServerToolCallEmitter,
 } from "../define-tool";
 
+import * as agentsRun from "./agents/run";
 import * as automationsCreate from "./automations/create";
 import * as automationsDelete from "./automations/delete";
 import * as automationsGet from "./automations/get";
@@ -46,6 +47,7 @@ const REGISTRARS = [
 	workspacesList,
 	workspacesCreate,
 	workspacesDelete,
+	agentsRun,
 	projectsList,
 	hostsList,
 ];
diff --git a/packages/mcp-v2/src/tools/workspaces/create.ts b/packages/mcp-v2/src/tools/workspaces/create.ts
index 016f3f47752..1378a79ea3e 100644
--- a/packages/mcp-v2/src/tools/workspaces/create.ts
+++ b/packages/mcp-v2/src/tools/workspaces/create.ts
@@ -3,11 +3,27 @@ import { z } from "zod";
 import { defineTool } from "../../define-tool";
 import { hostServiceMutation } from "../../host-service-client";
 
+const agentLaunchSchema = z.object({
+	agent: z
+		.string()
+		.min(1)
+		.describe(
+			"Agent preset id (e.g. `claude`, `codex`) or HostAgentConfig instance UUID.",
+		),
+	prompt: z.string().min(1).describe("Initial prompt the agent starts with."),
+	attachmentIds: z
+		.array(z.string().uuid())
+		.optional()
+		.describe(
+			"Host-scoped attachment UUIDs. The host resolves these to absolute paths and appends them to the prompt.",
+		),
+});
+
 export function register(server: McpServer): void {
 	defineTool(server, {
 		name: "workspaces_create",
 		description:
-			"Create a workspace on a host. A workspace is a branch-scoped working copy of a project. The host service materializes the git worktree on disk before returning. Provide exactly one of `branch` or `pr`. Use projects_list and hosts_list first to get the projectId and hostId.",
+			"Create a workspace on a host. A workspace is a branch-scoped working copy of a project. The host service materializes the git worktree on disk before returning. Provide exactly one of `branch` or `pr`. Optionally pass `agents` to spawn one or more agents in the workspace as soon as it is ready (each entry runs the equivalent of `agents_run` against the new workspace). Use projects_list and hosts_list first to get the projectId and hostId.",
 		inputSchema: {
 			projectId: z.string().uuid().describe("Project UUID."),
 			name: z.string().min(1).describe("Workspace name (display)."),
@@ -41,6 +57,12 @@ export function register(server: McpServer): void {
 				.uuid()
 				.optional()
 				.describe("Optional Superset task id to link to the new workspace."),
+			agents: z
+				.array(agentLaunchSchema)
+				.optional()
+				.describe(
+					"Agents to spawn in the workspace immediately after creation.",
+				),
 		},
 		handler: async (input, ctx) => {
 			return hostServiceMutation<
@@ -51,6 +73,11 @@ export function register(server: McpServer): void {
 					pr?: number;
 					baseBranch?: string;
 					taskId?: string;
+					agents?: Array<{
+						agent: string;
+						prompt: string;
+						attachmentIds?: string[];
+					}>;
 				},
 				{
 					workspace: {
@@ -60,7 +87,10 @@ export function register(server: McpServer): void {
 						branch: string;
 					};
 					terminals: Array<{ terminalId: string; label?: string }>;
-					agents: Array<unknown>;
+					agents: Array<
+						| { ok: true; sessionId: string; label: string }
+						| { ok: false; error: string }
+					>;
 					alreadyExists: boolean;
 				}
 			>(
@@ -78,6 +108,7 @@ export function register(server: McpServer): void {
 					pr: input.pr,
 					baseBranch: input.baseBranch,
 					taskId: input.taskId,
+					agents: input.agents,
 				},
 			);
 		},