Bazel MCP Server

Instructions

Implementation Reference

• index.ts:337-343 (handler)

  Core implementation of bazel_list_targets: runs `bazel query <path>/...` with optional additional args to list targets under the given path.

  async listTargets(path: string, additionalArgs?: string[], onOutput?: (chunk: string) => void): Promise<string> {
    const queryPattern = `${path}/...`;
    const validatedArgs = this.validateAdditionalArgs(additionalArgs);
    const allArgs = [queryPattern, ...validatedArgs];
    const { stdout } = await this.runBazelCommand("query", allArgs, onOutput);
    return stdout;
  }

• index.ts:552-560 (handler)

  Entry point handler in MCP CallToolRequest: validates 'path' argument and calls BazelClient.listTargets.

  case "bazel_list_targets": {
    const args = request.params.arguments as unknown as ListTargetsArgs;
    log(`Processing bazel_list_targets for path: ${args.path}`, 'info', false);
    if (!args.path) {
      throw new Error("Missing required argument: path");
    }
    response = await bazelClient.listTargets(args.path, args.additionalArgs);
    break;
  }

• index.ts:142-162 (schema)

  Tool schema: defines name, description, inputSchema with required 'path' (string) and optional 'additionalArgs' (string array).

  const listTargetsTool: Tool = {
    name: "bazel_list_targets",
    description: "List all available Bazel targets under a given path",
    inputSchema: {
      type: "object",
      properties: {
        path: {
          type: "string",
          description: "Path within the workspace to list targets for (e.g. '//path/to' or '//' for all targets)",
        },
        additionalArgs: {
          type: "array",
          items: {
            type: "string",
          },
          description: "Additional Bazel command line arguments (e.g. ['--output=build', '--keep_going'])",
        },
      },
      required: ["path"],
    },
  };

• index.ts:608-615 (registration)

  Registers bazel_list_targets (as listTargetsTool) among other tools in ListToolsResponse.

  tools: [
    buildTargetTool,
    queryTargetTool,
    testTargetTool,
    listTargetsTool,
    fetchDependenciesTool,
    setWorkspacePathTool,
  ],

• index.ts:55-58 (schema)

  TypeScript interface defining expected arguments for bazel_list_targets.

  interface ListTargetsArgs {
    path: string;
    additionalArgs?: string[];
  }