diff --git a/.src/commands/diff.ts b/.src/commands/diff.ts
new file mode 100644
index 0000000..1073730
--- /dev/null
+++ b/.src/commands/diff.ts
@@ -0,0 +1,141 @@
+import * as path from 'path';
+import { Command } from 'commander';
+import chalk from 'chalk';
+import {
+  getWorkspacePath,
+  loadWorkspaceConfig,
+  sanitizeAgentName
+} from '../utils/file-utils';
+import {
+  generateDiff,
+  createGit,
+  getCurrentBranch
+} from '../utils/git-utils';
+import { DiffLine } from '../types/index';
+import {
+  formatDiffAsMarkdown,
+  formatDiffAsJson,
+  formatDiffAsText,
+  exportDiffToFile,
+  generateShortDiffSummary
+} from '../utils/diff-utils';
+import { GitAgentSyncError, WorkspaceNotFoundError } from '../utils/errors';
+
+export function createDiffCommand(): Command {
+  const cmd = new Command('diff')
+    .description('Generate unified diffs for code review')
+    .argument('[agent-name]', 'Agent name (defaults to current workspace)')
+    .option('-o, --output <file>', 'Export diff to file')
+    .option('--short', 'Show short summary only')
+    .option('--json', 'Output as JSON')
+    .option('--text', 'Output as plain text')
+    .option('--compare <branch>', 'Compare to a specific branch (default: main)')
+    .action(async (agentName, options) => {
+      try {
+        const currentPath = process.cwd();
+        let workspacePath: string;
+        let targetAgentName: string;
+
+        if (agentName) {
+          targetAgentName = sanitizeAgentName(agentName);
+          workspacePath = getWorkspacePath(currentPath, targetAgentName);
+        } else {
+          const workspaceResult = await detectCurrentWorkspace(currentPath);
+          workspacePath = workspaceResult.path;
+          targetAgentName = workspaceResult.agentName;
+        }
+
+        const config = await loadWorkspaceConfig(workspacePath);
+        if (!config) {
+          throw new WorkspaceNotFoundError(targetAgentName);
+        }
+
+        const compareBranch = options.compare || config.mainBranch;
+        const diffResult = await generateDiff(currentPath, workspacePath, targetAgentName, compareBranch);
+
+        if (options.short) {
+          const summary = generateShortDiffSummary(diffResult);
+          console.log(chalk.white(`${targetAgentName}: ${summary}`));
+          return;
+        }
+
+        if (options.json) {
+          console.log(formatDiffAsJson(diffResult));
+          return;
+        }
+
+        if (options.text) {
+          console.log(formatDiffAsText(diffResult));
+          return;
+        }
+
+        if (options.output) {
+          await exportDiffToFile(diffResult, options.output, 'markdown');
+          console.log(chalk.green(`\n✓ Diff exported to ${options.output}`));
+          return;
+        }
+
+        console.log(chalk.cyan(`\n📝 Diff: ${targetAgentName}`));
+        console.log(chalk.gray(`Branch: ${diffResult.branch} → ${diffResult.comparedBranch}`));
+        console.log(chalk.gray('─'.repeat(60)));
+
+        if (diffResult.files.length === 0) {
+          console.log(chalk.yellow('\n   No differences found.'));
+          return;
+        }
+
+        console.log(chalk.cyan('\n📊 Summary:'));
+        console.log(`   Files: ${chalk.white(diffResult.summary.filesChanged)}`);
+        console.log(`   Additions: ${chalk.green(`+${diffResult.summary.additions}`)}`);
+        console.log(`   Deletions: ${chalk.red(`-${diffResult.summary.deletions}`)}`);
+        console.log(chalk.gray('─'.repeat(60)));
+
+        for (const file of diffResult.files) {
+          console.log(chalk.cyan(`\n📄 ${file.file}`));
+          console.log(`   +${file.additions} / -${file.deletions}`);
+
+          const relevantChanges = file.changes.filter((c: DiffLine) => c.type !== 'context').slice(0, 20);
+
+          if (relevantChanges.length > 0) {
+            console.log('   Preview:');
+            for (const line of relevantChanges) {
+              if (line.type === 'added') {
+                console.log(`   ${chalk.green(line.content)}`);
+              } else if (line.type === 'deleted') {
+                console.log(`   ${chalk.red(line.content)}`);
+              }
+            }
+
+            if (file.changes.filter((c: DiffLine) => c.type !== 'context').length > 20) {
+              console.log(`   ${chalk.gray('... and more changes (use --output to see full diff)')}`);
+            }
+          }
+        }
+
+        console.log(chalk.cyan('\n💡 Use --output to export full diff to a file'));
+
+      } catch (error) {
+        const gitError = error instanceof GitAgentSyncError ? error : new GitAgentSyncError(String(error));
+        console.error(chalk.red(`\n❌ Error: ${gitError.message}`));
+        process.exit(1);
+      }
+    });
+
+  return cmd;
+}
+
+async function detectCurrentWorkspace(currentPath: string): Promise<{ path: string; agentName: string }> {
+  const git = createGit(currentPath);
+  const branch = await getCurrentBranch(git);
+
+  if (branch.startsWith('agent-')) {
+    const agentName = branch.replace(/^agent-/, '');
+    const { getWorkspacePath } = await import('../utils/file-utils');
+    return {
+      agentName,
+      path: getWorkspacePath(currentPath, agentName)
+    };
+  }
+
+  throw new GitAgentSyncError('Not in an agent workspace. Please specify an agent name.');
+}