refactor: move more common code into base agent class

Moves the instructions and ignored files into the agent base class.

Author: crisbeto

runner/codegen/base-cli-agent-runner.ts

@@ -86,6 +86,54 @@ export abstract class BaseCliAgentRunner {
     this.pendingProcesses.clear();
   }
 
+  /** Gets patterns of files that likely all agents need to ignore. */
+  protected getCommonIgnorePatterns() {
+    return {
+      directories: [
+        '/dist',
+        '/tmp',
+        '/out-tsc',
+        '/bazel-out',
+        '/node_modules',
+        '/.angular/cache',
+        '.sass-cache/',
+        '.DS_Store',
+      ],
+      files: [
+        'npm-debug.log',
+        'yarn-error.log',
+        '.editorconfig',
+        '.postcssrc.json',
+        '.gitignore',
+        'yarn.lock',
+        'pnpm-lock.yaml',
+        'package-lock.json',
+        'pnpm-workspace.yaml',
+        'Thumbs.db',
+      ],
+    };
+  }
+
+  /** Gets the common system instructions for all agents. */
+  protected getCommonInstructions(options: LlmGenerateFilesRequestOptions) {
+    return [
+      `# Important Rules`,
+      `The following instructions dictate how you should behave. It is CRITICAL that you follow them AS CLOSELY AS POSSIBLE:`,
+      `- Do NOT attempt to improve the existing code, only implement the user request.`,
+      `- STOP once you've implemented the user request, do NOT try to clean up the project.`,
+      `- You ARE NOT ALLOWED to install dependencies. Assume that all necessary dependencies are already installed.`,
+      `- Do NOT clean up unused files.`,
+      `- Do NOT run the dev server, use \`${options.context.buildCommand}\` to verify the build correctness instead.`,
+      `- Do NOT use \`git\` or any other versioning software.`,
+      `- Do NOT attempt to lint the project.`,
+      '',
+      `Following the rules is VERY important and should be done with the utmost care!`,
+      '',
+      '',
+      options.context.systemInstructions,
+    ].join('\n');
+  }
+
   private resolveBinaryPath(binaryName: string): string {
     let dir = import.meta.dirname;
     let closestRoot: string | null = null;

runner/codegen/gemini-cli-runner.ts

@@ -0,0 +1,84 @@
+import {LlmGenerateFilesRequestOptions, LlmRunner} from './llm-runner.js';
+import {join} from 'path';
+import {mkdirSync} from 'fs';
+import {writeFile} from 'fs/promises';
+import {BaseCliAgentRunner} from './base-cli-agent-runner.js';
+
+const SUPPORTED_MODELS = ['gemini-2.5-pro', 'gemini-2.5-flash', 'gemini-2.5-flash-lite'];
+
+/** Runner that generates code using the Gemini CLI. */
+export class GeminiCliRunner extends BaseCliAgentRunner implements LlmRunner {
+  readonly id = 'gemini-cli';
+  readonly displayName = 'Gemini CLI';
+  readonly hasBuiltInRepairLoop = true;
+  protected ignoredFilePatterns = ['**/GEMINI.md', '**/.geminiignore'];
+  protected binaryName = 'gemini';
+
+  getSupportedModels(): string[] {
+    return SUPPORTED_MODELS;
+  }
+
+  protected getCommandLineFlags(options: LlmGenerateFilesRequestOptions): string[] {
+    return [
+      '--prompt',
+      options.context.executablePrompt,
+      '--model',
+      options.model,
+      // Skip all confirmations.
+      '--approval-mode',
+      'yolo',
+    ];
+  }
+
+  protected async writeAgentFiles(options: LlmGenerateFilesRequestOptions): Promise<void> {
+    const {context} = options;
+    const ignoreFilePath = join(context.directory, '.geminiignore');
+    const instructionFilePath = join(context.directory, 'GEMINI.md');
+    const settingsDir = join(context.directory, '.gemini');
+
+    mkdirSync(settingsDir);
+
+    const commonIgnorePatterns = super.getCommonIgnorePatterns();
+    const ignoreFileContent = [
+      ...commonIgnorePatterns.directories,
+      ...commonIgnorePatterns.files,
+    ].join('\n');
+
+    const promises: Promise<unknown>[] = [
+      writeFile(ignoreFilePath, ignoreFileContent),
+      writeFile(instructionFilePath, super.getCommonInstructions(options)),
+    ];
+
+    if (context.packageManager) {
+      writeFile(
+        join(settingsDir, 'settings.json'),
+        this.getGeminiSettingsFile(context.packageManager, context.possiblePackageManagers),
+      );
+    }
+
+    await Promise.all(promises);
+  }
+
+  private getGeminiSettingsFile(packageManager: string, possiblePackageManagers: string[]): string {
+    const config = {
+      excludeTools: [
+        // Prevent Gemini from using version control and package
+        // managers since doing so via prompting doesn't always work.
+        'run_shell_command(git)',
+        ...possiblePackageManagers
+          .filter(m => m !== packageManager)
+          .map(m => `run_shell_command(${m})`),
+
+        // Note that we don't block all commands,
+        // because the build commands also go through it.
+        `run_shell_command(${packageManager} install)`,
+        `run_shell_command(${packageManager} add)`,
+        `run_shell_command(${packageManager} remove)`,
+        `run_shell_command(${packageManager} update)`,
+        `run_shell_command(${packageManager} list)`,
+      ],
+    };
+
+    return JSON.stringify(config, null, 2);
+  }
+}

runner/codegen/gemini-cli/gemini-cli-runner.ts

@@ -1,5 +1,5 @@
 import {UserFacingError} from '../utils/errors.js';
-import type {GeminiCliRunner} from './gemini-cli/gemini-cli-runner.js';
+import type {GeminiCliRunner} from './gemini-cli-runner.js';
 import type {GenkitRunner} from './genkit/genkit-runner.js';
 
 interface AvailableRunners {
@@ -22,7 +22,7 @@ export async function getRunnerByName<T extends RunnerName>(name: T): Promise<Av
         m => new m.GenkitRunner() as AvailableRunners[T],
       );
     case 'gemini-cli':
-      return import('./gemini-cli/gemini-cli-runner.js').then(
+      return import('./gemini-cli-runner.js').then(
         m => new m.GeminiCliRunner() as AvailableRunners[T],
       );
     default:

runner/codegen/gemini-cli/gemini-files.ts

@@ -24,7 +24,7 @@ export {generateCodeAndAssess} from './orchestration/generate.js';
 export {groupSimilarReports} from './orchestration/grouping.js';
 export {type LlmRunner} from './codegen/llm-runner.js';
 export {GenkitRunner} from './codegen/genkit/genkit-runner.js';
-export {GeminiCliRunner} from './codegen/gemini-cli/gemini-cli-runner.js';
+export {GeminiCliRunner} from './codegen/gemini-cli-runner.js';
 export {getRunnerByName, type RunnerName} from './codegen/runner-creation.js';
 export {getEnvironmentByPath} from './configuration/environment-resolution.js';
 export {type Environment} from './configuration/environment.js';