feat(mcp): Adds dataconnect_compile tool to MCP server.

src/dataconnect/loadAll.ts

@@ -0,0 +1,8 @@
+import { load } from "./load";
+import type { Config } from "../config";
+import { readFirebaseJson } from "./fileUtils";
+
+export function loadAll(projectId: string, config: Config) {
+  const configs = readFirebaseJson(config);
+  return Promise.all(configs.map((c) => load(projectId, config, c.source)));
+}

src/experiments.ts

@@ -147,6 +147,11 @@ export const ALL_EXPERIMENTS = experiments({
     default: true,
     public: false,
   },
+  mcpalpha: {
+    shortDescription: "Opt-in to early MCP features before they're widely released.",
+    default: false,
+    public: false,
+  },
   apptesting: {
     shortDescription: "Adds experimental App Testing feature",
     public: true,

src/mcp/index.ts

@@ -54,7 +54,7 @@
 ] as const;
 
 export class FirebaseMcpServer {
   private _ready: boolean = false;
   private _readyPromises: { resolve: () => void; reject: (err: unknown) => void }[] = [];
   startupRoot?: string;
   cachedProjectRoot?: string;
@@ -86,7 +86,7 @@
       mcp_client_name: this.clientInfo?.name || "<unknown-client>",
       mcp_client_version: this.clientInfo?.version || "<unknown-version>",
     };
     trackGA4(event, { ...params, ...clientInfoParams });
   }
 
   constructor(options: { activeFeatures?: ServerFeature[]; projectRoot?: string }) {
@@ -104,11 +104,11 @@
     this.server.setRequestHandler(ListPromptsRequestSchema, this.mcpListPrompts.bind(this));
     this.server.setRequestHandler(GetPromptRequestSchema, this.mcpGetPrompt.bind(this));
 
     this.server.oninitialized = async () => {
       const clientInfo = this.server.getClientVersion();
       this.clientInfo = clientInfo;
       if (clientInfo?.name) {
         this.trackGA4("mcp_client_connected");
       }
       if (!this.clientInfo?.name) this.clientInfo = { name: "<unknown-client>" };
 
@@ -123,12 +123,12 @@
       return {};
     });
 
     this.detectProjectRoot();
     this.detectActiveFeatures();
   }
 
   /** Wait until initialization has finished. */
   ready() {
     if (this._ready) return Promise.resolve();
     return new Promise((resolve, reject) => {
       this._readyPromises.push({ resolve: resolve as () => void, reject });
@@ -139,7 +139,7 @@
     return this.clientInfo?.name ?? (isFirebaseStudio() ? "Firebase Studio" : "<unknown-client>");
   }
 
   private get clientConfigKey() {
     return `mcp.clientConfigs.${this.clientName}:${this.startupRoot || process.cwd()}`;
   }
 
@@ -227,6 +227,10 @@
   }
 
   get availablePrompts(): ServerPrompt[] {
+    this.log(
+      "debug",
+      `availablePrompts: ${JSON.stringify(this.activeFeatures)} // ${JSON.stringify(this.detectedFeatures)}`,
+    );
     return availablePrompts(
       this.activeFeatures?.length ? this.activeFeatures : this.detectedFeatures,
     );

src/mcp/prompts/dataconnect/index.ts

@@ -0,0 +1,9 @@
+import { isEnabled } from "../../../experiments";
+import { schema } from "./schema";
+import type { ServerPrompt } from "../../prompt";
+
+export const dataconnectPrompts: ServerPrompt[] = [];
+
+if (isEnabled("mcpalpha")) {
+  dataconnectPrompts.push(schema);
+}

src/mcp/prompts/dataconnect/schema.ts

@@ -0,0 +1,74 @@
+import { z } from "zod";
+import { prompt } from "../../prompt";
+import { loadAll } from "../../../dataconnect/loadAll";
+import type { ServiceInfo } from "../../../dataconnect/types";
+import { BUILTIN_SDL, MAIN_INSTRUCTIONS } from "../../util/dataconnect/content";
+import { compileErrors } from "../../util/dataconnect/compile";
+
+function renderServices(fdcServices: ServiceInfo[]) {
+  if (!fdcServices.length) return "Data Connect Status: <UNCONFIGURED>";
+
+  return `\n\n## Data Connect Schema
+
+The following is the up-to-date content of existing schema files (their paths are relative to the Data Connect source directory).
+
+${fdcServices[0].schema.source.files?.map((f) => `\`\`\`graphql ${f.path}\n${f.content}\n\`\`\``).join("\n\n")}`;
+}
+
+function renderErrors(errors?: string) {
+  return `\n\n## Current Schema Build Errors\n\n${errors || "<NO ERRORS>"}`;
+}
+
+export const schema = prompt(
+  {
+    name: "schema",
+    description: "Generate or update your Firebase Data Connect schema.",
+    arguments: [
+      {
+        name: "prompt",
+        description:
+          "describe the schema you want generated or the edits you want to make to your existing schema",
+        required: true,
+      },
+    ],
+    annotations: {
+      title: "Deploy to Firebase",
+    },
+  },
+  async ({ prompt }, { config, projectId, accountEmail }) => {
+    const fdcServices = await loadAll(projectId, config);
+    const buildErrors = fdcServices.length
+      ? await compileErrors(fdcServices[0].sourceDirectory)
+      : "";
+
+    return [
+      {
+        role: "user" as const,
+        content: {
+          type: "text",
+          text: `
+${MAIN_INSTRUCTIONS}\n\n${BUILTIN_SDL}
+
+==== CURRENT ENVIRONMENT INFO ====
+
+User Email: ${accountEmail || "<NONE>"}
+Project ID: ${projectId || "<NONE>"}
+${renderServices(fdcServices)}${renderErrors(buildErrors)}
+
+==== USER PROMPT ====
+
+${prompt}
+
+==== TASK INSTRUCTIONS ====
+
+1. If Data Connect is marked as \`<UNCONFIGURED>\`, first run the \`firebase_init\` tool with \`{dataconnect: {}}\` arguments to initialize it.
+2. If there is not an existing schema to work with (or the existing schema is the commented-out default schema about a movie app), follow the user's prompt to generate a robust schema meeting the specified requirements.
+3. If there is already a schema, perform edits to the existing schema file(s) based on the user's instructions. If schema build errors are present and seem relevant to your changes, attempt to fix them.
+4. After you have performed edits on the schema, run the \`dataconnect_compile\` tool to build the schema and see if there are any errors. Fix errors that are related to the user's prompt or your changes.
+5. If there are errors, attempt to fix them. If you have attempted to fix them 3 times without success, ask the user for help.
+6. If there are no errors, write a brief paragraph summarizing your changes.`,
+        },
+      },
+    ];
+  },
+);

src/mcp/prompts/index.ts

@@ -1,12 +1,13 @@
 import { ServerFeature } from "../types";
 import { ServerPrompt } from "../prompt";
 import { corePrompts } from "./core";
+import { dataconnectPrompts } from "./dataconnect";
 
 const prompts: Record<ServerFeature, ServerPrompt[]> = {
   core: corePrompts,
   firestore: [],
   storage: [],
-  dataconnect: [],
+  dataconnect: dataconnectPrompts,
   auth: [],
   messaging: [],
   remoteconfig: [],
@@ -36,7 +37,7 @@ function namespacePrompts(
 
 export function availablePrompts(features?: ServerFeature[]): ServerPrompt[] {
   const allPrompts: ServerPrompt[] = namespacePrompts(prompts["core"], "core");
-  if (!features) {
+  if (!features?.length) {
     features = Object.keys(prompts).filter((f) => f !== "core") as ServerFeature[];
   }
 

src/mcp/tools/dataconnect/compile.ts

@@ -0,0 +1,47 @@
+import { z } from "zod";
+import { tool } from "../../tool";
+import { pickService } from "../../../dataconnect/fileUtils";
+import { compileErrors } from "../../util/dataconnect/compile";
+
+export const compile = tool(
+  {
+    name: "compile",
+    description:
+      "Use this to compile Firebase Data Connect schema and/or operations and check for build errors.",
+    inputSchema: z.object({
+      error_filter: z
+        .enum(["all", "schema", "operations"])
+        .describe("filter errors to a specific type only. defaults to `all` if omitted.")
+        .optional(),
+      service_id: z
+        .string()
+        .optional()
+        .describe(
+          "The Firebase Data Connect service ID to look for. If omitted, the first service defined in `firebase.json` is used.",
+        ),
+    }),
+    annotations: {
+      title: "Compile Data Connect",
+      readOnlyHint: true,
+    },
+    _meta: {
+      requiresProject: false,
+      requiresAuth: false,
+    },
+  },
+  async ({ service_id, error_filter }, { projectId, config }) => {
+    const serviceInfo = await pickService(projectId, config, service_id || undefined);
+    const errors = await compileErrors(serviceInfo.sourceDirectory, error_filter);
+    if (errors)
+      return {
+        content: [
+          {
+            type: "text",
+            text: `The following errors were encountered while compiling Data Connect from directory \`${serviceInfo.sourceDirectory}\`:\n\n${errors}`,
+          },
+        ],
+        isError: true,
+      };
+    return { content: [{ type: "text", text: "Compiled successfully." }] };
+  },
+);

src/mcp/tools/dataconnect/execute_graphql.ts

@@ -3,9 +3,9 @@ import { z } from "zod";
 import { tool } from "../../tool";
 import * as dataplane from "../../../dataconnect/dataplaneClient";
 import { pickService } from "../../../dataconnect/fileUtils";
-import { graphqlResponseToToolResponse, parseVariables } from "./converter";
+import { graphqlResponseToToolResponse, parseVariables } from "../../util/dataconnect/converter";
 import { Client } from "../../../apiv2";
-import { getDataConnectEmulatorClient } from "./emulator";
+import { getDataConnectEmulatorClient } from "../../util/dataconnect/emulator";
 
 export const execute_graphql = tool(
   {

src/mcp/tools/dataconnect/execute_graphql_read.ts

@@ -3,9 +3,9 @@ import { z } from "zod";
 import { tool } from "../../tool";
 import * as dataplane from "../../../dataconnect/dataplaneClient";
 import { pickService } from "../../../dataconnect/fileUtils";
-import { graphqlResponseToToolResponse, parseVariables } from "./converter";
+import { graphqlResponseToToolResponse, parseVariables } from "../../util/dataconnect/converter";
 import { Client } from "../../../apiv2";
-import { getDataConnectEmulatorClient } from "./emulator";
+import { getDataConnectEmulatorClient } from "../../util/dataconnect/emulator";
 
 export const execute_graphql_read = tool(
   {

src/mcp/tools/dataconnect/execute_mutation.ts

@@ -4,9 +4,9 @@ import { tool } from "../../tool";
 import { mcpError } from "../../util";
 import * as dataplane from "../../../dataconnect/dataplaneClient";
 import { pickService } from "../../../dataconnect/fileUtils";
-import { graphqlResponseToToolResponse, parseVariables } from "./converter";
+import { graphqlResponseToToolResponse, parseVariables } from "../../util/dataconnect/converter";
 import { Client } from "../../../apiv2";
-import { getDataConnectEmulatorClient } from "./emulator";
+import { getDataConnectEmulatorClient } from "../../util/dataconnect/emulator";
 
 export const execute_mutation = tool(
   {

src/mcp/tools/dataconnect/execute_query.ts

@@ -4,9 +4,9 @@ import { tool } from "../../tool";
 import { mcpError } from "../../util";
 import * as dataplane from "../../../dataconnect/dataplaneClient";
 import { pickService } from "../../../dataconnect/fileUtils";
-import { graphqlResponseToToolResponse, parseVariables } from "./converter";
+import { graphqlResponseToToolResponse, parseVariables } from "../../util/dataconnect/converter";
 import { Client } from "../../../apiv2";
-import { getDataConnectEmulatorClient } from "./emulator";
+import { getDataConnectEmulatorClient } from "../../util/dataconnect/emulator";
 
 export const execute_query = tool(
   {

src/mcp/tools/dataconnect/get_connector.ts

@@ -3,7 +3,7 @@ import { tool } from "../../tool";
 import { toContent } from "../../util";
 import * as client from "../../../dataconnect/client";
 import { pickService } from "../../../dataconnect/fileUtils";
-import { connectorToText } from "./converter";
+import { connectorToText } from "../../util/dataconnect/converter";
 
 export const get_connectors = tool(
   {

src/mcp/tools/dataconnect/get_schema.ts

@@ -3,7 +3,7 @@ import { tool } from "../../tool";
 import { toContent } from "../../util";
 import * as client from "../../../dataconnect/client";
 import { pickService } from "../../../dataconnect/fileUtils";
-import { schemaToText } from "./converter";
+import { schemaToText } from "../../util/dataconnect/converter";
 
 export const get_schema = tool(
   {

src/mcp/tools/dataconnect/index.ts

@@ -8,8 +8,10 @@ import { execute_graphql } from "./execute_graphql";
 import { execute_graphql_read } from "./execute_graphql_read";
 import { execute_query } from "./execute_query";
 import { execute_mutation } from "./execute_mutation";
+import { compile } from "./compile";
 
 export const dataconnectTools: ServerTool[] = [
+  compile,
   list_services,
   generate_schema,
   generate_operation,

src/mcp/util/dataconnect/compile.ts

@@ -0,0 +1,21 @@
+import { prettify } from "../../../dataconnect/graphqlError";
+import { ServiceInfo } from "../../../dataconnect/types";
+import { DataConnectEmulator } from "../../../emulator/dataconnectEmulator";
+
+export async function compileErrors(
+  configDir: string,
+  errorFilter?: "all" | "schema" | "operations",
+) {
+  const errors = (await DataConnectEmulator.build({ configDir })).errors;
+  return (
+    errors
+      ?.filter((e) => {
+        const isOperationError = ["query", "mutation"].includes(e.path?.[0] as string);
+        if (errorFilter === "operations") return isOperationError;
+        if (errorFilter === "schema") return !isOperationError;
+        return true;
+      })
+      .map(prettify)
+      .join("\n") || ""
+  );
+}