fix(mcp): prompt arguments were not working correctly (#8976)

Author: mbleigh

src/mcp/index.ts

@@ -362,7 +362,7 @@ export class FirebaseMcpServer {
         name: p.mcp.name,
         description: p.mcp.description,
         annotations: p.mcp.annotations,
-        inputSchema: p.mcp.inputSchema,
+        arguments: p.mcp.arguments,
       })),
       _meta: {
         projectRoot: this.cachedProjectRoot,
@@ -377,7 +377,7 @@ export class FirebaseMcpServer {
   async mcpGetPrompt(req: GetPromptRequest): Promise<GetPromptResult> {
     await this.detectProjectRoot();
     const promptName = req.params.name;
-    const promptArgs = req.params.arguments;
+    const promptArgs = req.params.arguments || {};
     const prompt = this.getPrompt(promptName);
     if (!prompt) {
       throw new Error(`Prompt '${promptName}' could not be found.`);

src/mcp/prompt.ts

@@ -1,10 +1,7 @@
 import { PromptMessage } from "@modelcontextprotocol/sdk/types.js";
-import { z, ZodTypeAny } from "zod";
-import { zodToJsonSchema } from "zod-to-json-schema";
 import type { FirebaseMcpServer } from "./index";
 import type { Config } from "../config";
 import { RC } from "../rc";
-import { cleanSchema } from "./util";
 
 export interface ServerPromptContext {
   projectId: string;
@@ -14,11 +11,11 @@ export interface ServerPromptContext {
   rc: RC;
 }
 
-export interface ServerPrompt<InputSchema extends ZodTypeAny = ZodTypeAny> {
+export interface ServerPrompt {
   mcp: {
     name: string;
     description?: string;
-    inputSchema: any;
+    arguments?: { name: string; description?: string; required?: boolean }[];
     omitPrefix?: boolean;
     annotations?: {
       title?: string;
@@ -28,19 +25,12 @@ export interface ServerPrompt<InputSchema extends ZodTypeAny = ZodTypeAny> {
       feature?: string;
     };
   };
-  fn: (input: z.infer<InputSchema>, ctx: ServerPromptContext) => Promise<PromptMessage[]>;
+  fn: (args: Record<string, string>, ctx: ServerPromptContext) => Promise<PromptMessage[]>;
 }
 
-export function prompt<InputSchema extends ZodTypeAny>(
-  options: Omit<ServerPrompt<InputSchema>["mcp"], "inputSchema" | "name"> & {
-    name: string;
-    inputSchema: InputSchema;
-    omitPrefix?: boolean;
-  },
-  fn: ServerPrompt<InputSchema>["fn"],
-): ServerPrompt {
+export function prompt(options: ServerPrompt["mcp"], fn: ServerPrompt["fn"]): ServerPrompt {
   return {
-    mcp: { ...options, inputSchema: cleanSchema(zodToJsonSchema(options.inputSchema)) },
+    mcp: options,
     fn,
   };
 }

src/mcp/prompts/core/deploy.ts

@@ -1,17 +1,17 @@
-import { z } from "zod";
 import { prompt } from "../../prompt";
 
 export const deploy = prompt(
   {
     name: "deploy",
     omitPrefix: true,
     description: "Use this command to deploy resources to Firebase.",
-    inputSchema: z.object({
-      prompt: z
-        .string()
-        .describe("any specific instructions you wish to provide about deploying")
-        .optional(),
-    }),
+    arguments: [
+      {
+        name: "prompt",
+        description: "any specific instructions you wish to provide about deploying",
+        required: false,
+      },
+    ],
     annotations: {
       title: "Deploy to Firebase",
     },