diff --git a/packages/mcp-server/README.md b/packages/mcp-server/README.md
index fd4783ea9..dcc32aa94 100644
--- a/packages/mcp-server/README.md
+++ b/packages/mcp-server/README.md
@@ -4,6 +4,11 @@ MCP server exposing GSD orchestration tools for Claude Code, Cursor, and other M
 
 Start GSD auto-mode sessions, poll progress, resolve blockers, and retrieve results — all through the [Model Context Protocol](https://modelcontextprotocol.io/).
 
+This package now exposes two tool surfaces:
+
+- session/read tools for starting and inspecting GSD sessions
+- workflow mutation tools for planning, completion, validation, reassessment, and gate persistence
+
 ## Installation
 
 ```bash
@@ -69,6 +74,38 @@ Add to `.cursor/mcp.json`:
 
 ## Tools
 
+### Workflow mutation tools
+
+The workflow MCP surface includes:
+
+- `gsd_plan_milestone`
+- `gsd_plan_slice`
+- `gsd_replan_slice`
+- `gsd_slice_replan`
+- `gsd_task_complete`
+- `gsd_complete_task`
+- `gsd_slice_complete`
+- `gsd_complete_slice`
+- `gsd_validate_milestone`
+- `gsd_milestone_validate`
+- `gsd_complete_milestone`
+- `gsd_milestone_complete`
+- `gsd_reassess_roadmap`
+- `gsd_roadmap_reassess`
+- `gsd_save_gate_result`
+- `gsd_summary_save`
+- `gsd_milestone_status`
+
+These mutation tools use the same GSD workflow handlers as the native in-process tool path.
+
+Current support boundary:
+
+- when running inside the GSD monorepo checkout, the MCP server auto-discovers the shared workflow executor module
+- outside the monorepo, set `GSD_WORKFLOW_EXECUTORS_MODULE` to an importable `workflow-tool-executors` module path if you want the mutation tools enabled
+- session/read tools do not depend on this bridge
+
+If the executor bridge cannot be loaded, workflow mutation calls will fail with a precise configuration error instead of silently degrading.
+
 ### `gsd_execute`
 
 Start a GSD auto-mode session for a project directory.
@@ -175,6 +212,7 @@ Resolve a pending blocker in a session by sending a response to the blocked UI r
 | Variable | Description |
 |----------|-------------|
 | `GSD_CLI_PATH` | Absolute path to the GSD CLI binary. If not set, the server resolves `gsd` via `which`. |
+| `GSD_WORKFLOW_EXECUTORS_MODULE` | Optional absolute path or `file:` URL for the shared GSD workflow executor module used by workflow mutation tools. |
 
 ## Architecture
 
diff --git a/packages/mcp-server/src/server.ts b/packages/mcp-server/src/server.ts
index 0b65e13ef..f4f5fe206 100644
--- a/packages/mcp-server/src/server.ts
+++ b/packages/mcp-server/src/server.ts
@@ -1,9 +1,9 @@
 /**
- * MCP Server — registers GSD orchestration + read-only project state tools.
+ * MCP Server — registers GSD orchestration, project-state, and workflow tools.
  *
  * Session tools (6): gsd_execute, gsd_status, gsd_result, gsd_cancel, gsd_query, gsd_resolve_blocker
  * Read-only tools (6): gsd_progress, gsd_roadmap, gsd_history, gsd_doctor, gsd_captures, gsd_knowledge
- * Workflow tools (3): gsd_summary_save, gsd_task_complete, gsd_milestone_status
+ * Workflow tools (17): planning, replanning, completion, validation, reassessment, gate result, and milestone status tools
  *
  * Uses dynamic imports for @modelcontextprotocol/sdk because TS Node16
  * cannot resolve the SDK's subpath exports statically (same pattern as
@@ -117,7 +117,7 @@ interface McpServerInstance {
 // ---------------------------------------------------------------------------
 
 /**
- * Create and configure an MCP server with 12 GSD tools (6 session + 6 read-only).
+ * Create and configure an MCP server with session, read-only, and workflow tools.
  *
  * Returns the McpServer instance — call `connect(transport)` to start serving.
  * Uses dynamic imports for the MCP SDK to avoid TS subpath resolution issues.
diff --git a/packages/mcp-server/src/workflow-tools.ts b/packages/mcp-server/src/workflow-tools.ts
index 523005943..4784863fa 100644
--- a/packages/mcp-server/src/workflow-tools.ts
+++ b/packages/mcp-server/src/workflow-tools.ts
@@ -2,6 +2,8 @@
  * Workflow MCP tools — exposes the core GSD mutation/read handlers over MCP.
  */
 
+import { resolve } from "node:path";
+import { pathToFileURL } from "node:url";
 import { z } from "zod";
 
 const SUMMARY_ARTIFACT_TYPES = ["SUMMARY", "RESEARCH", "CONTEXT", "ASSESSMENT", "CONTEXT-DRAFT"] as const;
@@ -217,12 +219,46 @@ type WorkflowToolExecutors = {
 
 let workflowToolExecutorsPromise: Promise<WorkflowToolExecutors> | null = null;
 
+function toFileUrl(modulePath: string): string {
+  return pathToFileURL(resolve(modulePath)).href;
+}
+
+function getWorkflowExecutorModuleCandidates(env: NodeJS.ProcessEnv = process.env): string[] {
+  const candidates: string[] = [];
+  const explicitModule = env.GSD_WORKFLOW_EXECUTORS_MODULE?.trim();
+  if (explicitModule) {
+    candidates.push(
+      explicitModule.startsWith("file:") || explicitModule.startsWith("data:") ? explicitModule : toFileUrl(explicitModule),
+    );
+  }
+
+  candidates.push(
+    new URL("../../../src/resources/extensions/gsd/tools/workflow-tool-executors.js", import.meta.url).href,
+    new URL("../../../src/resources/extensions/gsd/tools/workflow-tool-executors.ts", import.meta.url).href,
+  );
+
+  return [...new Set(candidates)];
+}
+
 async function getWorkflowToolExecutors(): Promise<WorkflowToolExecutors> {
   if (!workflowToolExecutorsPromise) {
-    const jsUrl = new URL("../../../src/resources/extensions/gsd/tools/workflow-tool-executors.js", import.meta.url).href;
-    const tsUrl = new URL("../../../src/resources/extensions/gsd/tools/workflow-tool-executors.ts", import.meta.url).href;
-    workflowToolExecutorsPromise = import(jsUrl)
-      .catch(() => import(tsUrl)) as Promise<WorkflowToolExecutors>;
+    workflowToolExecutorsPromise = (async () => {
+      const attempts: string[] = [];
+      for (const candidate of getWorkflowExecutorModuleCandidates()) {
+        try {
+          return await import(candidate) as WorkflowToolExecutors;
+        } catch (err) {
+          attempts.push(`${candidate} (${err instanceof Error ? err.message : String(err)})`);
+        }
+      }
+
+      throw new Error(
+        "Unable to load GSD workflow executor bridge for MCP mutation tools. " +
+        "Set GSD_WORKFLOW_EXECUTORS_MODULE to an importable workflow-tool-executors module, " +
+        "or run the MCP server from a GSD checkout that includes src/resources/extensions/gsd/tools/workflow-tool-executors.(js|ts). " +
+        `Attempts: ${attempts.join("; ")}`,
+      );
+    })();
   }
   return workflowToolExecutorsPromise;
 }