diff --git a/CHANGELOG.md b/CHANGELOG.md
index 85b559613..95b72160f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -27,6 +27,7 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 
 - New `codegraph cycles` command lists the groups of files that import each other in a circle, as text or `--json`, and exits 1 when it finds any, so it works as a pre-commit or CI check (#888). Thanks @jiangyq9 and @goutham80808.
+- `codegraph init --local-only` keeps `.codegraph/` out of git entirely, so nothing of CodeGraph's shows in `git status`, and it works on a project that's already set up, leaving a `.codegraph/.gitignore` you've edited or committed alone (#910). Thanks @jadchene, @jiangyq9, @Wood-Q and @walterf3.
 
 ### Fixes
 
diff --git a/README.md b/README.md
index 8866ec732..b2eb521d7 100644
--- a/README.md
+++ b/README.md
@@ -529,7 +529,7 @@ The exact text is `src/mcp/server-instructions.ts` — the single source of trut
 codegraph                         # Run interactive installer
 codegraph install                 # Run installer (explicit)
 codegraph uninstall               # Remove CodeGraph from your agents AND the CLI (--keep-cli for configs only)
-codegraph init [path]             # Initialize a project + build its graph (one step)
+codegraph init [path]             # Initialize a project + build its graph (one step; --local-only keeps .codegraph/ out of git)
 codegraph uninit [path]           # Remove CodeGraph from a project (--force to skip prompt)
 codegraph index [path]            # Full index (--force to re-index, --quiet for less output)
 codegraph sync [path]             # Incremental update
diff --git a/__tests__/local-only-gitignore.test.ts b/__tests__/local-only-gitignore.test.ts
new file mode 100644
index 000000000..6dd6c908d
--- /dev/null
+++ b/__tests__/local-only-gitignore.test.ts
@@ -0,0 +1,275 @@
+/**
+ * `codegraph init --local-only` (#910): a `.codegraph/.gitignore` that ignores
+ * itself, so a project's CodeGraph data leaves no trace in `git status`.
+ *
+ * The default stays as it was, because a committed `.gitignore` is how a team
+ * shares the rule. So these also pin what must NOT be rewritten: a file with the
+ * user's own rules, and a file a repository has already committed.
+ */
+
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
+import { execFileSync, spawnSync } from 'child_process';
+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
+import { getCodeGraphDir, makeGitignoreLocalOnly } from '../src/directory';
+import CodeGraph from '../src/index';
+
+const BIN = path.resolve(__dirname, '../dist/bin/codegraph.js');
+
+// These index a project and spawn the real CLI, up to several times a test.
+vi.setConfig({ testTimeout: 60_000, hookTimeout: 60_000 });
+
+const LOCAL_ONLY = '*\n';
+const DEFAULT = `# CodeGraph data files — local to each machine, not for committing.
+# Ignore everything in .codegraph/ except this file itself, so transient
+# files (the database, daemon.pid, sockets, logs) never show up in git.
+*
+!.gitignore
+`;
+const STALE_DEFAULT = `# CodeGraph data files
+*.db
+*.db-wal
+*.db-shm
+cache/
+.dirty
+`;
+
+describe('local-only .codegraph/.gitignore', () => {
+  let dir: string;
+  let gitignore: string;
+
+  beforeEach(() => {
+    dir = fs.mkdtempSync(path.join(os.tmpdir(), 'codegraph-local-only-'));
+    gitignore = path.join(dir, '.codegraph', '.gitignore');
+    fs.writeFileSync(path.join(dir, 'a.ts'), 'export const a = 1;\n');
+  });
+
+  afterEach(() => {
+    fs.rmSync(dir, { recursive: true, force: true });
+  });
+
+  function seedGitignore(content: string): void {
+    fs.mkdirSync(path.dirname(gitignore), { recursive: true });
+    fs.writeFileSync(gitignore, content);
+  }
+
+  function git(...args: string[]): string {
+    return execFileSync('git', args, {
+      cwd: dir,
+      encoding: 'utf-8',
+      stdio: ['ignore', 'pipe', 'pipe'],
+      env: {
+        ...process.env,
+        GIT_AUTHOR_NAME: 'CodeGraph Test',
+        GIT_AUTHOR_EMAIL: 'codegraph-test@example.invalid',
+        GIT_COMMITTER_NAME: 'CodeGraph Test',
+        GIT_COMMITTER_EMAIL: 'codegraph-test@example.invalid',
+      },
+    });
+  }
+
+  function initRepo(): void {
+    git('init', '-q');
+    git('add', 'a.ts');
+    git('commit', '-qm', 'baseline');
+  }
+
+  function codegraph(...args: string[]): { code: number | null; output: string } {
+    const run = spawnSync(process.execPath, [BIN, ...args], {
+      cwd: dir,
+      encoding: 'utf-8',
+      env: { ...process.env, CODEGRAPH_NO_DAEMON: '1', NO_COLOR: '1', DO_NOT_TRACK: '1', CODEGRAPH_TELEMETRY: '0' },
+    });
+    return { code: run.status, output: run.stdout + run.stderr };
+  }
+
+  describe('makeGitignoreLocalOnly', () => {
+    it('writes the wildcard alone when there is no file', () => {
+      fs.mkdirSync(path.dirname(gitignore));
+
+      expect(makeGitignoreLocalOnly(dir)).toBe('written');
+      expect(fs.readFileSync(gitignore, 'utf-8')).toBe(LOCAL_ONLY);
+    });
+
+    it('writes into the directory the project really uses', () => {
+      const custom = process.env.CODEGRAPH_DIR;
+      process.env.CODEGRAPH_DIR = '.cg-custom';
+      try {
+        fs.mkdirSync(getCodeGraphDir(dir));
+
+        expect(makeGitignoreLocalOnly(dir)).toBe('written');
+        expect(fs.readFileSync(path.join(dir, '.cg-custom', '.gitignore'), 'utf-8')).toBe(LOCAL_ONLY);
+      } finally {
+        if (custom === undefined) delete process.env.CODEGRAPH_DIR;
+        else process.env.CODEGRAPH_DIR = custom;
+      }
+    });
+
+    it('replaces the default CodeGraph generates, as the code generates it', () => {
+      CodeGraph.initSync(dir).close();
+      expect(fs.readFileSync(gitignore, 'utf-8')).toBe(DEFAULT);
+
+      expect(makeGitignoreLocalOnly(dir)).toBe('written');
+      expect(fs.readFileSync(gitignore, 'utf-8')).toBe(LOCAL_ONLY);
+    });
+
+    it('replaces a default checked out with Windows line endings', () => {
+      seedGitignore(DEFAULT.replace(/\n/g, '\r\n'));
+
+      expect(makeGitignoreLocalOnly(dir)).toBe('written');
+      expect(fs.readFileSync(gitignore, 'utf-8')).toBe(LOCAL_ONLY);
+    });
+
+    it('replaces a default from before the wildcard', () => {
+      seedGitignore(STALE_DEFAULT);
+
+      expect(makeGitignoreLocalOnly(dir)).toBe('written');
+      expect(fs.readFileSync(gitignore, 'utf-8')).toBe(LOCAL_ONLY);
+    });
+
+    it.each([
+      ['with a newline', '*\n'],
+      ['with a Windows newline', '*\r\n'],
+    ])('leaves a file that is already local-only, %s', (_label, content) => {
+      seedGitignore(content);
+
+      expect(makeGitignoreLocalOnly(dir)).toBe('unchanged');
+      expect(fs.readFileSync(gitignore, 'utf-8')).toBe(content);
+    });
+
+    it.each([
+      ['the user wrote', 'codegraph.db\n'],
+      ['we generated and the user added to', `${DEFAULT}!shared-notes.md\n`],
+    ])('leaves a file %s', (_label, content) => {
+      seedGitignore(content);
+
+      expect(makeGitignoreLocalOnly(dir)).toBe('customized');
+      expect(fs.readFileSync(gitignore, 'utf-8')).toBe(content);
+    });
+
+    it('leaves a default the repository has committed', () => {
+      seedGitignore(DEFAULT);
+      initRepo();
+      git('add', '.codegraph/.gitignore');
+      git('commit', '-qm', 'share the rule');
+
+      expect(makeGitignoreLocalOnly(dir)).toBe('tracked');
+      expect(fs.readFileSync(gitignore, 'utf-8')).toBe(DEFAULT);
+      expect(git('status', '--porcelain')).toBe('');
+    });
+
+    it('replaces a default that is only untracked', () => {
+      seedGitignore(DEFAULT);
+      initRepo();
+
+      expect(makeGitignoreLocalOnly(dir)).toBe('written');
+    });
+
+    it('works outside a git repository', () => {
+      seedGitignore(DEFAULT);
+
+      expect(makeGitignoreLocalOnly(dir)).toBe('written');
+    });
+  });
+
+  describe('codegraph init', () => {
+    it('leaves nothing in git status with --local-only', () => {
+      initRepo();
+
+      const { code, output } = codegraph('init', '-y', '--local-only');
+
+      expect(code).toBe(0);
+      expect(output).toContain('.codegraph/.gitignore now ignores itself');
+      expect(fs.readFileSync(gitignore, 'utf-8')).toBe(LOCAL_ONLY);
+      expect(git('status', '--porcelain')).toBe('');
+    });
+
+    it('still builds the index', () => {
+      codegraph('init', '-y', '--local-only');
+
+      expect(fs.existsSync(path.join(dir, '.codegraph', 'codegraph.db'))).toBe(true);
+      expect(codegraph('status').output).toContain('typescript');
+    });
+
+    it('keeps its default without the flag', () => {
+      initRepo();
+
+      const { code, output } = codegraph('init', '-y');
+
+      expect(code).toBe(0);
+      expect(output).not.toContain('ignores itself');
+      expect(fs.readFileSync(gitignore, 'utf-8')).toBe(DEFAULT);
+      expect(git('status', '--porcelain')).toContain('.codegraph/');
+    });
+
+    it('converts an initialized project, without indexing it again', () => {
+      initRepo();
+      codegraph('init', '-y');
+      const db = path.join(dir, '.codegraph', 'codegraph.db');
+      const indexed = fs.statSync(db).mtimeMs;
+
+      const { code, output } = codegraph('init', '-y', '--local-only');
+
+      expect(code).toBe(0);
+      expect(output).toContain('Already initialized');
+      expect(output).toContain('.codegraph/.gitignore now ignores itself');
+      expect(fs.statSync(db).mtimeMs).toBe(indexed);
+      expect(git('status', '--porcelain')).toBe('');
+    });
+
+    it('says so when there is nothing to convert', () => {
+      codegraph('init', '-y', '--local-only');
+
+      expect(codegraph('init', '-y', '--local-only').output).toContain('.codegraph/.gitignore already ignores itself');
+    });
+
+    it('survives everything that opens the index afterwards', () => {
+      codegraph('init', '-y', '--local-only');
+
+      expect(codegraph('sync').code).toBe(0);
+      expect(codegraph('status').code).toBe(0);
+      expect(codegraph('index', '--quiet').code).toBe(0);
+      expect(codegraph('init', '-y').code).toBe(0);
+      expect(fs.readFileSync(gitignore, 'utf-8')).toBe(LOCAL_ONLY);
+    });
+
+    it('says why it left a file with the user\'s own rules', () => {
+      seedGitignore('codegraph.db\n');
+
+      const { code, output } = codegraph('init', '-y', '--local-only');
+
+      expect(code).toBe(0);
+      expect(output).toContain('Left .codegraph/.gitignore as it is because it has your own rules');
+      expect(fs.readFileSync(gitignore, 'utf-8')).toBe('codegraph.db\n');
+    });
+
+    it('says why it left a committed file, and shows no change in git', () => {
+      seedGitignore(DEFAULT);
+      initRepo();
+      git('add', '.codegraph/.gitignore');
+      git('commit', '-qm', 'share the rule');
+
+      const { code, output } = codegraph('init', '-y', '--local-only');
+
+      expect(code).toBe(0);
+      expect(output).toContain('Left .codegraph/.gitignore as it is because it is committed');
+      expect(git('status', '--porcelain')).toBe('');
+    });
+
+    it('refuses an unsafe root before touching anything', () => {
+      const home = spawnSync(process.execPath, [BIN, 'init', '-y', '--local-only'], {
+        cwd: os.homedir(),
+        encoding: 'utf-8',
+        env: { ...process.env, CODEGRAPH_NO_DAEMON: '1', NO_COLOR: '1' },
+      });
+
+      expect(home.status).toBe(1);
+      expect(fs.existsSync(path.join(os.homedir(), '.codegraph', '.gitignore'))).toBe(false);
+    });
+
+    it('offers the flag in --help', () => {
+      expect(codegraph('init', '--help').output).toContain('--local-only');
+    });
+  });
+});
diff --git a/site/src/content/docs/reference/cli.md b/site/src/content/docs/reference/cli.md
index 46b2bfd40..5425ee7fb 100644
--- a/site/src/content/docs/reference/cli.md
+++ b/site/src/content/docs/reference/cli.md
@@ -7,7 +7,7 @@ description: Every CodeGraph command and the flags it accepts.
 codegraph                         # Run interactive installer
 codegraph install                 # Run installer (explicit)
 codegraph uninstall               # Remove CodeGraph from your agents (inverse of install)
-codegraph init [path]             # Initialize a project + build its graph (one step)
+codegraph init [path]             # Initialize a project + build its graph (--local-only)
 codegraph uninit [path]           # Remove CodeGraph from a project (--force to skip prompt)
 codegraph index [path]            # Full re-index from scratch (--force, --quiet, --verbose)
 codegraph sync [path]             # Incremental update (--quiet)
@@ -36,6 +36,8 @@ The MCP server (`codegraph serve --mcp`) is launched automatically by your agent
 
 `codegraph init` creates the local `.codegraph/` directory **and** builds the full graph in one step. (The old `-i`/`--index` flag is now a no-op, accepted only so existing scripts don't break.) After that the file watcher keeps the graph current automatically — `index` (a full rebuild from scratch) and `sync` (an incremental update) are only needed when the watcher is disabled or you're scripting against the index outside an agent session.
 
+`.codegraph/` holds a `.gitignore` that keeps the index out of git and is itself meant to be committed, so the rule is shared with your team. If you use CodeGraph on your own, `codegraph init --local-only` makes that file ignore itself too, so nothing shows in `git status`. It also works on a project that's already initialized, without re-indexing. A `.gitignore` you've edited or committed is left as it is.
+
 ## status
 
 `codegraph status` shows what is in the index, including how many files each language has. When only some of a language's files yielded symbols, its row says how many did:
diff --git a/src/bin/codegraph.ts b/src/bin/codegraph.ts
index ebee81f6d..83194b4c8 100644
--- a/src/bin/codegraph.ts
+++ b/src/bin/codegraph.ts
@@ -55,7 +55,7 @@ try {
 import { Command } from 'commander';
 import * as path from 'path';
 import * as fs from 'fs';
-import { getCodeGraphDir, isInitialized, hasSchemalessDb, hasForeignDbFile, unsafeIndexRootReason, findNearestCodeGraphRoot, planFrontload, isTaskNotification, isAgentMessage, isCrossSessionMessage, stripSystemReminders, hasStructuralKeyword, extractCodeTokens, capPromptHookInjection, codeGraphDirName, DEFAULT_CODEGRAPH_DIR } from '../directory';
+import { getCodeGraphDir, makeGitignoreLocalOnly, isInitialized, hasSchemalessDb, hasForeignDbFile, unsafeIndexRootReason, findNearestCodeGraphRoot, planFrontload, isTaskNotification, isAgentMessage, isCrossSessionMessage, stripSystemReminders, hasStructuralKeyword, extractCodeTokens, capPromptHookInjection, codeGraphDirName, DEFAULT_CODEGRAPH_DIR } from '../directory';
 import { extractProseCandidates } from '../search/identifier-segments';
 import { detectWorktreeIndexMismatch, worktreeMismatchWarning } from '../sync/worktree';
 import { createShimmerProgress } from '../ui/shimmer-progress';
@@ -707,6 +707,28 @@ async function recordIndexTelemetry(
 // Commands
 // =============================================================================
 
+/** `init --local-only`: make the project's `.gitignore` ignore itself, and say what happened. */
+function applyLocalOnlyGitignore(
+  clack: { log: { success(message: string): void; info(message: string): void; warn(message: string): void } },
+  projectPath: string,
+): void {
+  const file = `${path.basename(getCodeGraphDir(projectPath))}/.gitignore`;
+  switch (makeGitignoreLocalOnly(projectPath)) {
+    case 'written':
+      clack.log.success(`${file} now ignores itself, so nothing of CodeGraph's shows in git.`);
+      break;
+    case 'unchanged':
+      clack.log.info(`${file} already ignores itself.`);
+      break;
+    case 'customized':
+      clack.log.warn(`Left ${file} as it is because it has your own rules. A lone * in it would keep the whole folder out of git.`);
+      break;
+    case 'tracked':
+      clack.log.warn(`Left ${file} as it is because it is committed to this repository, so changing it would show up in git.`);
+      break;
+  }
+}
+
 /**
  * The `init` flow — shared by `codegraph init` and `codegraph install --init`
  * (#1578): refuse an unsafe root, create `.codegraph/`, build the initial
@@ -717,7 +739,7 @@ async function recordIndexTelemetry(
  */
 async function runInit(
   projectPath: string,
-  options: { index?: boolean; force?: boolean; verbose?: boolean; yes?: boolean },
+  options: { index?: boolean; force?: boolean; verbose?: boolean; yes?: boolean; localOnly?: boolean },
 ): Promise<void> {
   const clack = await importESM('@clack/prompts');
 
@@ -739,6 +761,7 @@ async function runInit(
     if (isInitialized(projectPath)) {
       clack.log.warn(`Already initialized in ${projectPath}`);
       clack.log.info('Use "codegraph index" to re-index or "codegraph sync" to update');
+      if (options.localOnly) applyLocalOnlyGitignore(clack, projectPath);
       try {
         const { offerWatchFallback } = await import('../installer');
         await offerWatchFallback(clack, projectPath, { yes: options.yes });
@@ -761,6 +784,7 @@ async function runInit(
     const { default: CodeGraph, getDatabasePath } = await loadCodeGraph();
     const cg = await CodeGraph.init(projectPath, { index: false });
     clack.log.success(`Initialized in ${projectPath}`);
+    if (options.localOnly) applyLocalOnlyGitignore(clack, projectPath);
     // A fresh index on a Windows drive under WSL gets its own directory (#995).
     // It isn't the documented name, so say where it went and why.
     const dataDir = path.basename(getCodeGraphDir(projectPath));
@@ -831,7 +855,8 @@ program
   .option('-f, --force', 'Initialize even if the path looks like your home directory or a filesystem root')
   .option('-v, --verbose', 'Show detailed worker lifecycle and memory info')
   .option('-y, --yes', 'Non-interactive: skip every prompt and take the defaults (for scripts / CI / container bootstraps)')
-  .action(async (pathArg: string | undefined, options: { index?: boolean; force?: boolean; verbose?: boolean; yes?: boolean }) => {
+  .option('--local-only', 'Keep .codegraph/ out of git entirely: its .gitignore ignores itself too. Also converts an initialized project')
+  .action(async (pathArg: string | undefined, options: { index?: boolean; force?: boolean; verbose?: boolean; yes?: boolean; localOnly?: boolean }) => {
     await runInit(path.resolve(pathArg || process.cwd()), options);
   });
 
diff --git a/src/directory.ts b/src/directory.ts
index 56277ee1a..ef76af713 100644
--- a/src/directory.ts
+++ b/src/directory.ts
@@ -4,6 +4,7 @@
  * Manages the .codegraph/ directory structure for CodeGraph data.
  */
 
+import { execFileSync } from 'child_process';
 import * as fs from 'fs';
 import * as os from 'os';
 import * as path from 'path';
@@ -955,6 +956,62 @@ function ensureGitignore(gitignorePath: string): boolean {
   }
 }
 
+/**
+ * The local-only `.codegraph/.gitignore` (#910): the wildcard alone, which
+ * ignores this file too, so nothing of CodeGraph's shows in `git status` and
+ * nothing asks to be committed. It carries no header, so `ensureGitignore`
+ * treats it as the user's own and leaves it alone from then on.
+ */
+const LOCAL_ONLY_GITIGNORE_CONTENT = '*\n';
+
+/** What `makeGitignoreLocalOnly` did. */
+export type LocalOnlyGitignoreResult =
+  /** The file is local-only now. */
+  | 'written'
+  /** It already was. */
+  | 'unchanged'
+  /** It holds rules CodeGraph didn't write, so it was left alone. */
+  | 'customized'
+  /** It is committed, so rewriting it would show up as a change. Left alone. */
+  | 'tracked';
+
+/** Whether git tracks `file`. False outside a repository, or without git. */
+function isTrackedByGit(file: string): boolean {
+  try {
+    execFileSync('git', ['ls-files', '--error-unmatch', '--', path.basename(file)], {
+      cwd: path.dirname(file),
+      stdio: 'ignore',
+      windowsHide: true,
+      timeout: 10_000,
+    });
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+/**
+ * Make `.codegraph/.gitignore` local-only, for `codegraph init --local-only`.
+ * Only a file CodeGraph generated is replaced: anything else, or one a project
+ * has committed to share the rule, stays as it is and the caller says why.
+ */
+export function makeGitignoreLocalOnly(projectRoot: string): LocalOnlyGitignoreResult {
+  const gitignorePath = path.join(getCodeGraphDir(projectRoot), '.gitignore');
+  let existing: string | null;
+  try {
+    existing = fs.readFileSync(gitignorePath, 'utf-8').replace(/\r\n/g, '\n');
+  } catch {
+    existing = null;
+  }
+  if (existing === LOCAL_ONLY_GITIGNORE_CONTENT) return 'unchanged';
+  if (existing !== null) {
+    if (existing !== GITIGNORE_CONTENT && !isStaleDefaultGitignore(existing)) return 'customized';
+    if (isTrackedByGit(gitignorePath)) return 'tracked';
+  }
+  fs.writeFileSync(gitignorePath, LOCAL_ONLY_GITIGNORE_CONTENT, 'utf-8');
+  return 'written';
+}
+
 /**
  * Create the .codegraph directory structure
  * Note: Only throws if codegraph.db already exists, not just if .codegraph/ exists.