diff --git a/packages/navie/src/command.ts b/packages/navie/src/command.ts
index 4baace09fa..b0411a3cdb 100644
--- a/packages/navie/src/command.ts
+++ b/packages/navie/src/command.ts
@@ -12,6 +12,7 @@ export enum CommandMode {
   Suggest = 'suggest',
   Observe = 'observe',
   Review = 'review',
+  Diff = 'diff',
   Welcome = 'welcome',
 }
 
diff --git a/packages/navie/src/commands/diff-command.ts b/packages/navie/src/commands/diff-command.ts
new file mode 100644
index 0000000000..3563444a35
--- /dev/null
+++ b/packages/navie/src/commands/diff-command.ts
@@ -0,0 +1,47 @@
+import Command, { CommandRequest } from '../command';
+import { ProjectInfo } from '../project-info';
+import ProjectInfoService from '../services/project-info-service';
+
+// Define output formats: text, json, jsonl
+export type DiffOutputFormat = 'text' | 'json' | 'jsonl';
+
+export interface ProjectDiffInfo {
+  directory: string;
+  diff?: string;
+}
+
+// Transform ProjectInfo to ProjectDiffInfo
+export function projectInfoToProjectDiffInfo(projectInfo: ProjectInfo): ProjectDiffInfo {
+  return {
+    directory: projectInfo.directory,
+    diff: projectInfo.diff,
+  };
+}
+
+export default class DiffCommand implements Command {
+  constructor(private readonly projectInfoService: ProjectInfoService) {}
+
+  async *execute(request: CommandRequest): AsyncIterable<string> {
+    const outputFormat = request.userOptions.stringValue('format') || 'text';
+    const baseBranch = request.userOptions.stringValue('base');
+
+    const projectInfoResponse = await this.projectInfoService.lookupProjectInfo(true, baseBranch);
+    const projectInfo = Array.isArray(projectInfoResponse)
+      ? projectInfoResponse
+      : [projectInfoResponse];
+
+    if (outputFormat === 'text') {
+      for (const info of projectInfo) {
+        yield `Changes in ${info.directory}:\n`;
+        yield info.diff || 'No changes detected.';
+        yield '\n';
+      }
+    } else if (outputFormat === 'json') {
+      yield JSON.stringify(projectInfo.map(projectInfoToProjectDiffInfo), null, 2);
+    } else if (outputFormat === 'jsonl') {
+      for (const info of projectInfo) {
+        yield JSON.stringify(projectInfoToProjectDiffInfo(info)) + '\n';
+      }
+    }
+  }
+}
diff --git a/packages/navie/src/navie.ts b/packages/navie/src/navie.ts
index 1bb6ebf9f1..bd1b59e1ce 100644
--- a/packages/navie/src/navie.ts
+++ b/packages/navie/src/navie.ts
@@ -41,6 +41,7 @@ import ReviewCommand from './commands/review-command';
 import WelcomeCommand from './commands/welcome-command';
 import InvokeTestsService from './services/invoke-tests-service';
 import { TestInvocationProvider } from './test-invocation';
+import DiffCommand from './commands/diff-command';
 
 export type ChatHistory = Message[];
 
@@ -195,6 +196,8 @@ export default function navie(
       projectInfoService
     );
 
+  const buildDiffCommand = () => new DiffCommand(projectInfoService);
+
   const buildReviewCommand = () =>
     new ReviewCommand(
       options,
@@ -217,6 +220,7 @@ export default function navie(
     [CommandMode.Suggest]: buildSuggestCommand,
     [CommandMode.Observe]: buildObserveCommand,
     [CommandMode.Review]: buildReviewCommand,
+    [CommandMode.Diff]: buildDiffCommand,
     [CommandMode.Welcome]: buildWelcomeCommand,
   };