diff --git a/README.md b/README.md
index 0e77c3a..1ee5df6 100644
--- a/README.md
+++ b/README.md
@@ -45,6 +45,7 @@ All TypeScript is executed directly via `tsx` — no build step required for dev
 | `@agentry/claude` | Claude Code driver (`claude -p --output-format stream-json`) |
 | `@agentry/codex` | Codex CLI driver (`codex exec --json`) |
 | `@agentry/gemini` | Gemini CLI driver (`gemini -p --output-format stream-json`) |
+| `@agentry/antigravity` | Antigravity driver (`agy -p --output-format stream-json`) |
 | `@agentry/mcp` | `MockMcpServer` (JSON-RPC + stdio shim) + MCP matchers |
 | `agentry` | CLI (`agentry test`, `record`, `init`, `doctor`) |
 
@@ -249,6 +250,7 @@ The SPEC describes the full vision. What is implemented vs. planned:
 - Claude driver (`claude -p --output-format stream-json`)
 - Codex driver (`codex exec --json`)
 - Gemini driver (`gemini -p --output-format stream-json`; coalesces streaming assistant deltas)
+- Antigravity driver (`agy -p --output-format stream-json`; event-stream normalization faithful, sandbox fs-diff best-effort since agy uses its own scratch dir)
 - Normalized causal event model (`tool_use`, `tool_result`, `mcp_request`, `llm_request`/`llm_response`, `message`, `usage`, `run.end`, `plugin`, `skill`, `fs`)
 - Assertions, Tiers 1–3: `toHaveToolCall`, `toHaveCalledToolTimes`, `toUseToolsFrom`, `toHaveCalledAll`, `toHaveMcpRequest`, `toFinishWithin`, `toHaveFile`, `toMatchSchema`
 - Skill/plugin effect matchers: `toHaveLoadedPlugin`, `toFireHook` (CH2) and `toInjectContext`, `toRegisterTools` (CH1, via the proxy)
diff --git a/packages/antigravity/package.json b/packages/antigravity/package.json
new file mode 100644
index 0000000..6a3c485
--- /dev/null
+++ b/packages/antigravity/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "@agentry/antigravity",
+  "version": "0.0.0",
+  "type": "module",
+  "description": "Agentry driver for Antigravity (agy) headless stream-json.",
+  "exports": { ".": "./src/index.ts" },
+  "publishConfig": {
+    "exports": { ".": { "types": "./dist/index.d.ts", "default": "./dist/index.js" } }
+  },
+  "scripts": { "build": "tsup src/index.ts --format esm --dts --clean" },
+  "dependencies": { "@agentry/core": "workspace:*" }
+}
diff --git a/packages/antigravity/src/driver.ts b/packages/antigravity/src/driver.ts
new file mode 100644
index 0000000..9a5e314
--- /dev/null
+++ b/packages/antigravity/src/driver.ts
@@ -0,0 +1,206 @@
+/**
+ * Antigravity (`agy`) driver. Drives `agy -p --output-format stream-json`
+ * headlessly (stdin ignored so the CLI never blocks) and normalizes the native
+ * `event`-discriminated stream into AgentEvents.
+ *
+ * `parseAntigravityEvents` is a pure whole-stream mapping (native events →
+ * AgentEvents) so it can be unit-tested without spawning the CLI. Note: agy
+ * writes to its own project/scratch dir by default, so sandbox fs-diff capture
+ * is best-effort even though event-stream normalization is faithful.
+ */
+import { spawn } from 'node:child_process';
+import { createInterface } from 'node:readline';
+import {
+  EventFactory,
+  RunRecord,
+  type AgentDriver,
+  type AgentEvent,
+  type DriverCapabilities,
+  type RunOptions,
+  type RunResult,
+  type RunEndReason,
+  type Usage,
+  isEvent,
+} from '@agentry/core';
+
+/* eslint-disable @typescript-eslint/no-explicit-any */
+type Raw = any;
+
+/** Map a full agy `stream-json` stream into the normalized AgentEvent stream. */
+export function parseAntigravityEvents(raws: Raw[], f: EventFactory, runId: string): AgentEvent[] {
+  const out: AgentEvent[] = [];
+  let bufferIndex: number | undefined;
+  let bufferText = '';
+
+  const flush = () => {
+    if (bufferIndex === undefined) return;
+    out.push(
+      f.make(
+        { type: 'message', role: 'assistant', text: bufferText },
+        { turnId: `step-${bufferIndex}`, source: 'agent', agentNativeType: 'agent_response' },
+      ),
+    );
+    bufferIndex = undefined;
+    bufferText = '';
+  };
+
+  for (const raw of raws) {
+    const event = raw?.event;
+
+    if (event === 'init') {
+      out.push(
+        f.make(
+          { type: 'run.start', runId, agent: 'antigravity', model: raw.model ?? '' },
+          { turnId: 'init', source: 'agent', agentNativeType: 'init', raw },
+        ),
+      );
+      continue;
+    }
+
+    if (event === 'step_update') {
+      const su = raw.step_update ?? {};
+      if (su.step_type === 'tool') {
+        if (bufferIndex !== undefined && su.step_index !== bufferIndex) flush();
+        if (su.state === 'ACTIVE') {
+          out.push(
+            f.make(
+              { type: 'tool_use', id: String(su.step_index), name: su.tool_name, args: su.tool_info?.parameters },
+              { turnId: `step-${su.step_index}`, source: 'agent', capability: 'tool', agentNativeType: 'step_update/tool', raw: su },
+            ),
+          );
+        } else if (su.state === 'DONE') {
+          out.push(
+            f.make(
+              { type: 'tool_result', id: String(su.step_index), name: su.tool_name, result: su.tool_info?.result, isError: false },
+              { turnId: `step-${su.step_index}`, source: 'agent', capability: 'tool', agentNativeType: 'step_update/tool', raw: su },
+            ),
+          );
+        }
+      } else if (su.step_type === 'agent_response' && su.text_delta !== undefined) {
+        if (bufferIndex !== undefined && su.step_index !== bufferIndex) flush();
+        bufferIndex = su.step_index;
+        bufferText += su.text_delta;
+      } else if (bufferIndex !== undefined && su.step_index !== bufferIndex) {
+        flush();
+      }
+      continue;
+    }
+
+    if (event === 'result') {
+      flush();
+      const r = raw.result ?? {};
+      const u = r.usage ?? {};
+      out.push(
+        f.make(
+          {
+            type: 'usage',
+            inputTokens: u.input_tokens ?? 0,
+            outputTokens: u.output_tokens ?? 0,
+            cacheReadTokens: u.cache_read_tokens,
+          },
+          { turnId: 'result', source: 'agent', agentNativeType: 'result.usage', raw: u },
+        ),
+      );
+      const reason: RunEndReason = r.status === 'SUCCESS' ? 'completed' : 'error';
+      out.push(
+        f.make(
+          { type: 'run.end', runId, exitCode: r.status === 'SUCCESS' ? 0 : 1, reason },
+          { turnId: 'result', source: 'agent', agentNativeType: 'result', raw },
+        ),
+      );
+      continue;
+    }
+  }
+
+  flush();
+  return out;
+}
+
+/** Aggregate the authoritative usage (from the terminal `result` usage event). */
+function aggregateUsage(events: AgentEvent[]): Usage {
+  const totals: Usage = { inputTokens: 0, outputTokens: 0 };
+  for (const e of events) {
+    if (isEvent(e, 'usage')) {
+      totals.inputTokens += e.payload.inputTokens;
+      totals.outputTokens += e.payload.outputTokens;
+      if (e.payload.cacheReadTokens !== undefined) {
+        totals.cacheReadTokens = (totals.cacheReadTokens ?? 0) + e.payload.cacheReadTokens;
+      }
+    }
+  }
+  return totals;
+}
+
+export function buildArgs(opts: RunOptions): string[] {
+  const args = ['-p', opts.prompt, '--output-format', 'stream-json', '--model', opts.model, '--add-dir', opts.cwd];
+  if (opts.permissionMode === 'bypassPermissions') args.push('--dangerously-skip-permissions');
+  if (opts.extraArgs?.length) args.push(...opts.extraArgs);
+  return args;
+}
+
+let runCounter = 0;
+
+export class AntigravityDriver implements AgentDriver {
+  readonly id = 'antigravity';
+  constructor(private readonly bin = process.env.AGENTRY_ANTIGRAVITY_BIN ?? 'agy') {}
+
+  capabilities(): DriverCapabilities {
+    return {
+      structuredStream: true,
+      llmInterception: 'none',
+      mcpTransports: [],
+      toolPermissionControl: true,
+      nativeBudgetControl: false,
+    };
+  }
+
+  async run(opts: RunOptions): Promise<RunRecord> {
+    const runId = `antigravity-${runCounter++}`;
+    const factory = new EventFactory(runId);
+    const raws: unknown[] = [];
+
+    const child = spawn(this.bin, buildArgs(opts), {
+      cwd: opts.cwd,
+      env: { ...process.env, ...opts.env },
+      stdio: ['ignore', 'pipe', 'pipe'],
+    });
+
+    const rl = createInterface({ input: child.stdout });
+    rl.on('line', (line) => {
+      const s = line.trim();
+      if (!s) return;
+      try {
+        raws.push(JSON.parse(s));
+      } catch {
+        return; // tolerate non-JSON noise
+      }
+    });
+
+    let stderr = '';
+    child.stderr.on('data', (d) => (stderr += String(d)));
+
+    let timer: NodeJS.Timeout | undefined;
+    const exitCode = await new Promise<number | null>((resolve, reject) => {
+      child.on('error', reject);
+      child.on('close', (code) => resolve(code));
+      if (opts.timeoutMs) timer = setTimeout(() => child.kill('SIGTERM'), opts.timeoutMs);
+      opts.signal?.addEventListener('abort', () => child.kill('SIGTERM'), { once: true });
+    }).finally(() => timer && clearTimeout(timer));
+
+    const events = parseAntigravityEvents(raws, factory, runId);
+
+    const ended = events.find((e) => isEvent(e, 'run.end'));
+    const reason: RunEndReason = ended && isEvent(ended, 'run.end') ? ended.payload.reason : exitCode === 0 ? 'completed' : 'crash';
+    if (!ended) {
+      events.push(
+        factory.make(
+          { type: 'run.end', runId, exitCode, reason },
+          { turnId: 'result', source: 'runner', agentNativeType: 'synthetic' },
+        ),
+      );
+    }
+
+    const result: RunResult = { exitCode, reason, usage: aggregateUsage(events) };
+    return new RunRecord(events, result);
+  }
+}
diff --git a/packages/antigravity/src/index.ts b/packages/antigravity/src/index.ts
new file mode 100644
index 0000000..ac3cec7
--- /dev/null
+++ b/packages/antigravity/src/index.ts
@@ -0,0 +1,2 @@
+// @agentry/antigravity — antigravity driver.
+export * from './driver';
diff --git a/packages/antigravity/test/build-args.test.ts b/packages/antigravity/test/build-args.test.ts
new file mode 100644
index 0000000..6e0a9c8
--- /dev/null
+++ b/packages/antigravity/test/build-args.test.ts
@@ -0,0 +1,33 @@
+import { describe, it, expect } from 'vitest';
+import type { RunOptions } from '@agentry/core';
+import { buildArgs } from '../src/driver';
+
+const base: RunOptions = { prompt: 'write hello.txt', model: 'claude-sonnet-4-6', cwd: '/tmp/x' };
+
+describe('buildArgs', () => {
+  it('emits the headless stream-json base invocation', () => {
+    expect(buildArgs(base)).toEqual([
+      '-p',
+      'write hello.txt',
+      '--output-format',
+      'stream-json',
+      '--model',
+      'claude-sonnet-4-6',
+      '--add-dir',
+      '/tmp/x',
+    ]);
+  });
+
+  it('adds --dangerously-skip-permissions for bypassPermissions', () => {
+    expect(buildArgs({ ...base, permissionMode: 'bypassPermissions' })).toContain('--dangerously-skip-permissions');
+  });
+
+  it('omits --dangerously-skip-permissions by default', () => {
+    expect(buildArgs(base)).not.toContain('--dangerously-skip-permissions');
+  });
+
+  it('appends extraArgs verbatim at the end', () => {
+    const args = buildArgs({ ...base, extraArgs: ['--foo', 'bar'] });
+    expect(args.slice(-2)).toEqual(['--foo', 'bar']);
+  });
+});
diff --git a/packages/antigravity/test/parse.test.ts b/packages/antigravity/test/parse.test.ts
new file mode 100644
index 0000000..ac53cbb
--- /dev/null
+++ b/packages/antigravity/test/parse.test.ts
@@ -0,0 +1,104 @@
+import { describe, it, expect } from 'vitest';
+import { EventFactory, RunRecord, isEvent, type AgentEvent } from '@agentry/core';
+import { parseAntigravityEvents } from '../src/driver';
+
+// Captured agy stream-json ground-truth sample.
+const SAMPLE = [
+  {
+    event: 'init',
+    conversation_id: 'c1',
+    init: { cwd: '/tmp/x', tools: ['write_to_file', 'run_command'], permission_mode: 'bypass' },
+  },
+  {
+    event: 'step_update',
+    step_update: { conversation_id: 'c1', step_index: 0, state: 'DONE', step_type: 'user_input' },
+  },
+  {
+    event: 'step_update',
+    step_update: {
+      conversation_id: 'c1',
+      step_index: 3,
+      state: 'DONE',
+      step_type: 'agent_response',
+      usage: { input_tokens: 16947, output_tokens: 702, thinking_tokens: 619, cache_read_tokens: 0, total_tokens: 17649 },
+    },
+  },
+  {
+    event: 'step_update',
+    step_update: {
+      conversation_id: 'c1',
+      step_index: 4,
+      state: 'ACTIVE',
+      step_type: 'tool',
+      tool_name: 'write_to_file',
+      tool_info: { name: 'write_to_file', parameters: { TargetFile: 'hello.txt' } },
+    },
+  },
+  {
+    event: 'step_update',
+    step_update: {
+      conversation_id: 'c1',
+      step_index: 4,
+      state: 'DONE',
+      step_type: 'tool',
+      tool_name: 'write_to_file',
+      tool_info: { name: 'write_to_file', parameters: { TargetFile: 'hello.txt' } },
+    },
+  },
+  {
+    event: 'step_update',
+    step_update: { conversation_id: 'c1', step_index: 7, state: 'ACTIVE', step_type: 'agent_response', text_delta: 'done' },
+  },
+  {
+    event: 'step_update',
+    step_update: { conversation_id: 'c1', step_index: 7, state: 'DONE', step_type: 'agent_response', text_delta: '.' },
+  },
+  {
+    event: 'result',
+    result: {
+      conversation_id: 'c1',
+      status: 'SUCCESS',
+      response: 'done.',
+      duration_seconds: 12,
+      num_turns: 1,
+      usage: { input_tokens: 22664, output_tokens: 1084, thinking_tokens: 923, cache_read_tokens: 12164, total_tokens: 23748 },
+    },
+  },
+];
+
+function parseAll(): AgentEvent[] {
+  const f = new EventFactory('r', () => 0);
+  return parseAntigravityEvents(SAMPLE, f, 'r');
+}
+
+describe('parseAntigravityEvents', () => {
+  const events = parseAll();
+  const rec = new RunRecord(events);
+
+  it('maps init to run.start with the antigravity agent', () => {
+    const start = events.find((e) => isEvent(e, 'run.start'));
+    expect(start && isEvent(start, 'run.start') && start.payload.agent).toBe('antigravity');
+  });
+
+  it('maps the tool step to a tool call', () => {
+    expect(rec.toolCalls).toHaveLength(1);
+    expect(rec.toolCalls[0]!.payload.name).toBe('write_to_file');
+    expect(rec.toolCalls[0]!.payload.args).toEqual({ TargetFile: 'hello.txt' });
+  });
+
+  it('coalesces agent_response text_delta by step_index into one message', () => {
+    expect(rec.assistantMessages).toHaveLength(1);
+    expect(rec.lastMessage).toBe('done.');
+  });
+
+  it('maps the terminal result to authoritative usage + run.end completed', () => {
+    const usage = events.filter((e) => isEvent(e, 'usage'));
+    expect(usage).toHaveLength(1);
+    expect(rec.usage.inputTokens).toBe(22664);
+    expect(rec.usage.outputTokens).toBe(1084);
+    const u = usage[0]!;
+    expect(isEvent(u, 'usage') && u.payload.cacheReadTokens).toBe(12164);
+    const end = events.find((e) => isEvent(e, 'run.end'));
+    expect(end && isEvent(end, 'run.end') && end.payload.reason).toBe('completed');
+  });
+});
diff --git a/packages/antigravity/tsconfig.json b/packages/antigravity/tsconfig.json
new file mode 100644
index 0000000..972facb
--- /dev/null
+++ b/packages/antigravity/tsconfig.json
@@ -0,0 +1,5 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": { "outDir": "dist", "rootDir": "src" },
+  "include": ["src"]
+}
diff --git a/packages/cli/package.json b/packages/cli/package.json
index a6192ca..91846b8 100644
--- a/packages/cli/package.json
+++ b/packages/cli/package.json
@@ -15,6 +15,7 @@
     "@agentry/claude": "workspace:*",
     "@agentry/codex": "workspace:*",
     "@agentry/gemini": "workspace:*",
+    "@agentry/antigravity": "workspace:*",
     "@agentry/mcp": "workspace:*"
   }
 }
diff --git a/packages/cli/src/commands/doctor.ts b/packages/cli/src/commands/doctor.ts
index 76655b6..989fce3 100644
--- a/packages/cli/src/commands/doctor.ts
+++ b/packages/cli/src/commands/doctor.ts
@@ -2,6 +2,7 @@ import { spawnSync } from 'node:child_process';
 import { ClaudeDriver } from '@agentry/claude';
 import { CodexDriver } from '@agentry/codex';
 import { GeminiDriver } from '@agentry/gemini';
+import { AntigravityDriver } from '@agentry/antigravity';
 
 /** \`agentry doctor\` — probe installed agent CLIs and print driver capabilities. */
 export async function cmdDoctor(): Promise<number> {
@@ -48,5 +49,19 @@ export async function cmdDoctor(): Promise<number> {
   for (const [k, val] of Object.entries(gcaps)) {
     console.log(`    ${k}: ${JSON.stringify(val)}`);
   }
+
+  const agyBin = process.env.AGENTRY_ANTIGRAVITY_BIN ?? 'agy';
+  const av = spawnSync(agyBin, ['--version'], { encoding: 'utf8' });
+  if (av.status === 0) {
+    console.log(`\n  agy      ✓  ${av.stdout.trim()}`);
+  } else {
+    console.log(`\n  agy      ✗  not found (looked for '${agyBin}')`);
+  }
+
+  console.log('\n  antigravity driver capabilities:');
+  const agyCaps = new AntigravityDriver().capabilities();
+  for (const [k, val] of Object.entries(agyCaps)) {
+    console.log(`    ${k}: ${JSON.stringify(val)}`);
+  }
   return 0;
 }
diff --git a/packages/cli/src/commands/run.ts b/packages/cli/src/commands/run.ts
index c318f1e..eb2636e 100644
--- a/packages/cli/src/commands/run.ts
+++ b/packages/cli/src/commands/run.ts
@@ -16,6 +16,7 @@ import {
 import { ClaudeDriver } from '@agentry/claude';
 import { CodexDriver } from '@agentry/codex';
 import { GeminiDriver } from '@agentry/gemini';
+import { AntigravityDriver } from '@agentry/antigravity';
 import { discoverTests } from '../discover';
 
 function selectDriver(agent: string | undefined): AgentDriver {
@@ -24,6 +25,8 @@ function selectDriver(agent: string | undefined): AgentDriver {
       return new CodexDriver();
     case 'gemini':
       return new GeminiDriver();
+    case 'antigravity':
+      return new AntigravityDriver();
     case 'claude':
     default:
       return new ClaudeDriver();
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index e4f4b1e..b1a228d 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -30,6 +30,12 @@ importers:
         specifier: workspace:*
         version: link:../../packages/cli
 
+  packages/antigravity:
+    dependencies:
+      '@agentry/core':
+        specifier: workspace:*
+        version: link:../core
+
   packages/claude:
     dependencies:
       '@agentry/core':
@@ -38,6 +44,9 @@ importers:
 
   packages/cli:
     dependencies:
+      '@agentry/antigravity':
+        specifier: workspace:*
+        version: link:../antigravity
       '@agentry/claude':
         specifier: workspace:*
         version: link:../claude
diff --git a/tsconfig.json b/tsconfig.json
index 68f78e1..0a190c3 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -8,6 +8,7 @@
       "@agentry/claude": ["packages/claude/src/index.ts"],
       "@agentry/codex": ["packages/codex/src/index.ts"],
       "@agentry/gemini": ["packages/gemini/src/index.ts"],
+      "@agentry/antigravity": ["packages/antigravity/src/index.ts"],
       "@agentry/mcp": ["packages/mcp/src/index.ts"]
     }
   },
diff --git a/vitest.config.ts b/vitest.config.ts
index 19081f4..2c0c0db 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -11,6 +11,7 @@ export default defineConfig({
       '@agentry/claude': new URL('./packages/claude/src/index.ts', import.meta.url).pathname,
       '@agentry/codex': new URL('./packages/codex/src/index.ts', import.meta.url).pathname,
       '@agentry/gemini': new URL('./packages/gemini/src/index.ts', import.meta.url).pathname,
+      '@agentry/antigravity': new URL('./packages/antigravity/src/index.ts', import.meta.url).pathname,
       '@agentry/mcp': new URL('./packages/mcp/src/index.ts', import.meta.url).pathname,
     },
   },