block · sanjay3290 · Aug 21, 2026
@@ -9,7 +9,7 @@ Buzz Relay ──WS──→ buzz-acp ──stdio──→ Your Agent
                                        (send_message, etc.)
 ```
 
-Supports any agent that speaks [ACP](https://agentclientprotocol.com/) over stdio: **goose**, **codex** (via [codex-acp](https://github.com/agentclientprotocol/codex-acp)), and **claude code** (via [claude-agent-acp](https://github.com/agentclientprotocol/claude-agent-acp)).
+Supports any agent that speaks [ACP](https://agentclientprotocol.com/) over stdio: **goose**, **codex** (via [codex-acp](https://github.com/agentclientprotocol/codex-acp)), **claude code** (via [claude-agent-acp](https://github.com/agentclientprotocol/claude-agent-acp)), and **google antigravity** (via `agy` on `PATH`, PATH-probed preset — no bundled installer).
 
 ## Prerequisites
 
@@ -98,6 +98,25 @@ buzz-acp
 Older installs that still expose `claude-code-acp` are also supported. `buzz-acp`
 treats both Claude ACP command names as the same zero-arg runtime.
 
+## Running with Google Antigravity
+
+Google Antigravity is exposed in Buzz as a PATH-probed preset (`agy` on `PATH`). Buzz does **not** bundle or download an `agy_acp_server` binary — install `agy` via Google's official Antigravity distribution and ensure `agy` is on `PATH`.
+
+```bash
+# 1. Verify agy is on PATH
+agy --version
+
+# 2. Run with buzz-acp (no BUZZ_ACP_AGENT_ARGS needed for agy)
+export BUZZ_PRIVATE_KEY="nsec1..."
+export BUZZ_ACP_AGENT_COMMAND="agy"
+
+buzz-acp
+```
+
+Buzz Desktop shows the `agy` harness when `agy` is found on `PATH` (via `common_binary_paths` + login-shell `PATH`). When unavailable, the catalog entry shows `Not installed` with a link to `https://antigravity.google`.
+
+> **Note:** `agy` currently exposes `agent`, `mcp`, `models`, `plugin`, `update` subcommands and `--print --output-format stream-json` (no ACP `agy_acp_server` / `session/new` mode was found on the tested `agy 1.1.17` binary). A future ACP shim (`agy -p --output-format stream-json`) or tier-2 preset with no installer is the honest integration path until Google publishes an ACP endpoint.
+
 ## Configuration
 
 All configuration is via environment variables (or CLI flags — every env var has a matching flag).
@@ -267,7 +286,7 @@ Buzz Desktop supports registering any ACP-speaking agent tool as a selectable ru
 
 ### How it works
 
-**Tier-1 — compiled-in runtimes** (Goose, Claude Code, Codex, Buzz Agent): have auto-installers, auth probes, and first-class onboarding. Their IDs (`goose`, `claude`, `codex`, `buzz-agent`) are reserved and cannot be overridden.
+**Tier-1 — compiled-in runtimes** (Goose, Claude Code, Codex, Buzz Agent): have auto-installers, auth probes, and first-class onboarding. Their IDs (`goose`, `claude`, `codex`, `buzz-agent`) are reserved and cannot be overridden. **Antigravity** (`antigravity` / `agy`) is currently a tier-1 ID reservation with PATH probing only — no managed download — to avoid alias collision and to allow a future managed or shim integration without ID breakage.
 
 **Tier-2 — preset catalog** (Cursor, Oh My Pi, Grok Build, OpenCode, Kimi Code, Amp, Hermes Agent, OpenClaw): static `HarnessDefinition` entries in `desktop/src-tauri/src/managed_agents/discovery.rs` (`PRESET_HARNESSES`). They are always present in the runtime catalog, PATH-probed for availability, not editable or deletable by the user. Displayed with bundled logos; if not installed, a docs link appears instead.
 
@@ -318,7 +337,7 @@ To add a new runtime to the tier-2 gallery:
 4. **Add a bundled logo** (64×64 PNG or optimised SVG) to `desktop/public/harness-logos/<id>.png` and add a corresponding entry to `PRESET_LOGOS` in `desktop/src/features/onboarding/ui/RuntimeIcon.tsx`. Record the source and license in `desktop/public/harness-logos/CREDITS.md`. Only bundle a mark whose upstream license permits redistribution; skipping this step is caught by `presetLogos.test.mjs`, which asserts every `PRESET_HARNESSES` id has a mapped logo that exists on disk.
 5. Run `cargo test --lib` and `just desktop-typecheck` to verify everything compiles.
 
-The built-in `BUILTIN_IDS` set (`goose`, `claude`, `codex`, `buzz-agent`, and all current preset ids) is the reserved namespace; every other id is available for custom harnesses.
+The built-in `BUILTIN_IDS` set (`goose`, `claude`, `codex`, `antigravity`, `buzz-agent`, and all current preset ids) is the reserved namespace; every other id is available for custom harnesses.
 
 ## Using Any ACP Agent
 

@@ -715,8 +715,8 @@ pub(crate) fn normalize_agent_command_identity(command: &str) -> String {
         .expect("rsplit always yields at least one element");
     let lower = basename.to_ascii_lowercase();
     // Windows resolves commands through `.exe` binaries and npm's `.cmd`/`.bat`
-    // shims; all three name the same runtime identity.
-    let stem = [".exe", ".cmd", ".bat"]
+    // shims; Python/PEX artifacts use `.par` on Unix/macOS; all name the same runtime identity.
+    let stem = [".exe", ".cmd", ".bat", ".par"]
         .iter()
         .find_map(|extension| lower.strip_suffix(extension))
         .unwrap_or(&lower);
@@ -728,9 +728,10 @@ pub(crate) fn normalize_agent_command_identity(command: &str) -> String {
         .collect()
 }
 
-fn default_agent_args(command: &str) -> Option<Vec<String>> {
+pub(crate) fn default_agent_args(command: &str) -> Option<Vec<String>> {
     match normalize_agent_command_identity(command).as_str() {
         "goose" => Some(vec!["acp".to_string()]),
+        "antigravity" | "google-antigravity" | "agy" | "agy-acp-server" => Some(Vec::new()),
         "codex" | "codex-acp" | "claude-agent-acp" | "claude-code-acp" | "claude-code"
         | "claudecode" | "buzz-agent" => Some(Vec::new()),
         _ => None,
@@ -825,9 +826,12 @@ pub fn normalize_agent_args(command: &str, agent_args: Vec<String>) -> Vec<Strin
     }
 
     // Older callers relied on the Goose-specific default even for runtimes like
-    // Codex and Claude. Treat that legacy fallback as "no args" for zero-arg
-    // providers so desktop- and env-based launches behave the same way.
-    if normalized.len() == 1 && normalized[0].eq_ignore_ascii_case("acp") && default_args.is_empty()
+    // Codex, Claude, and Antigravity. Treat that legacy fallback as the runtime's
+    // default args for non-Goose providers so desktop- and env-based launches
+    // behave the same way.
+    if normalized.len() == 1
+        && normalized[0].eq_ignore_ascii_case("acp")
+        && normalize_agent_command_identity(command) != "goose"
     {
         return default_args;
     }
@@ -1666,6 +1670,28 @@ mod tests {
             normalize_agent_command_identity(r"C:\Tools\Hermes\HERMES-AGENT.BAT"),
             "hermes-agent"
         );
+        // Antigravity .par and .exe artifacts.
+        assert_eq!(
+            normalize_agent_command_identity("agy_acp_server.par"),
+            "agy-acp-server"
+        );
+        assert_eq!(
+            normalize_agent_command_identity("AGY_ACP_SERVER.PAR"),
+            "agy-acp-server"
+        );
+        assert_eq!(
+            normalize_agent_command_identity("/opt/google/bin/agy_acp_server.par"),
+            "agy-acp-server"
+        );
+        assert_eq!(
+            normalize_agent_command_identity("antigravity"),
+            "antigravity"
+        );
+        assert_eq!(
+            normalize_agent_command_identity("google-antigravity"),
+            "google-antigravity"
+        );
+        assert_eq!(normalize_agent_command_identity("agy"), "agy");
         // Non-ASCII must not panic.
         assert_eq!(normalize_agent_command_identity("my-agënt"), "my-agënt");
         // Edge cases: empty, whitespace-only, bare separators.
@@ -1675,6 +1701,43 @@ mod tests {
         assert_eq!(normalize_agent_command_identity("///"), "");
     }
 
+    #[test]
+    fn default_agent_args_empty_for_antigravity_on_all_platforms() {
+        for cmd in [
+            "antigravity",
+            "agy",
+            "google-antigravity",
+            "agy_acp_server",
+            "agy_acp_server.par",
+            "agy_acp_server.exe",
+            "/usr/local/bin/agy_acp_server.par",
+            r"C:\Tools\agy_acp_server.exe",
+        ] {
+            assert_eq!(
+                default_agent_args(cmd),
+                Some(Vec::<String>::new()),
+                "expected empty args for {cmd}"
+            );
+            assert_eq!(normalize_agent_args(cmd, Vec::new()), Vec::<String>::new());
+            assert_eq!(
+                normalize_agent_args(cmd, vec!["acp".into()]),
+                Vec::<String>::new()
+            );
+        }
+    }
+
+    #[test]
+    fn normalize_agent_args_preserves_explicit_custom_antigravity_args() {
+        assert_eq!(
+            normalize_agent_args("antigravity", vec!["--flag".into(), "val".into()]),
+            vec!["--flag", "val"]
+        );
+        assert_eq!(
+            normalize_agent_args("agy", vec!["--model".into(), "gemini".into()]),
+            vec!["--model", "gemini"]
+        );
+    }
+
     #[test]
     fn default_agent_env_recognizes_hermes_identities() {
         for command in [

@@ -15,6 +15,7 @@ license permits redistribution.
 | `omp.svg` | [can1357/oh-my-pi](https://github.com/can1357/oh-my-pi) | `667111575ebba136dadfd6989379e7f67e0d40d9` | MIT © 2025 Mario Zechner; © 2025–2026 Can Bölük | `assets/icon.svg` | None |
 | `kimi.png` | [MoonshotAI/kimi-cli](https://github.com/MoonshotAI/kimi-cli) | `4a550effdfcb29a25a5d325bf935296cc50cd417` | Apache-2.0; NOTICE: Kimi Code CLI © 2025 Moonshot AI | `web/public/logo.png` | None |
 | `grok.svg` | [SpaceXAI brand guidelines](https://x.ai/legal/brand-guidelines) | Retrieved 2026-07-25 | xAI Brand Guidelines: marks may be used to accurately refer to xAI or its services; logos must be used exactly as provided | `SpaceXAI_Grok_Assets.zip` → `Grok_Logomark_Dark.svg` | None |
+| `antigravity.svg` | Placeholder neutral mark for Antigravity harness | 2026-08-20 | Neutral geometric placeholder (not a Google brand asset); nominative use only | `desktop/src/features/onboarding/ui/HarnessMarks.tsx` four-point star path | Scaled to 24×24 viewBox, `currentColor` |
 
 ## Inline SVG marks (`RUNTIME_MARKS`)
 
@@ -26,6 +27,7 @@ Monochrome marks inlined as `currentColor` paths in
 |---|---|---|---|---|---|
 | Goose | [block/goose](https://github.com/block/goose) | `305849b71709b95b86ed9f11bd3bc939899c0aab` | Apache-2.0 © Block, Inc. | `documentation/static/img/goose.svg` | `fill="#101010"` → `currentColor`; dropped the redundant clipPath wrapper |
 | Cursor | [simple-icons](https://github.com/simple-icons/simple-icons) | `16.27.1` (slug `cursor`) | CC0-1.0 (path data); nominative use of the Cursor mark to identify Cursor's harness | `icons/cursor.svg` | `fill` → `currentColor` |
+| Antigravity | Neutral placeholder | 2026-08-20 | Neutral placeholder mark (not a Google brand asset) | `desktop/src/features/onboarding/ui/HarnessMarks.tsx` `AntigravityMark` | `fill` → `currentColor`; single four-point star path |
 
 Codex deliberately has **no** bundled mark: the OpenAI blossom was removed
 from simple-icons in v16 at the vendor's request, so we do not ship it —

@@ -220,7 +220,7 @@ pub(crate) fn validate_harness_definition_pub(def: &HarnessDefinition) -> Result
 /// tier-1 runtimes — no hand-maintained copy.  Adding a preset to
 /// `PRESET_HARNESSES` automatically reserves its ID without a separate edit.
 fn builtin_ids() -> impl Iterator<Item = &'static str> {
-    const TIER1: &[&str] = &["goose", "claude", "codex", "buzz-agent"];
+    const TIER1: &[&str] = &["goose", "claude", "codex", "buzz-agent", "antigravity"];
     let tier2 = crate::managed_agents::discovery::preset_harness_ids();
     TIER1.iter().copied().chain(tier2.iter().copied())
 }
@@ -537,7 +537,7 @@ mod tests {
     #[test]
     fn builtin_ids_are_rejected() {
         // Tier-1 hard-coded IDs must always be reserved.
-        for id in &["goose", "claude", "codex", "buzz-agent"] {
+        for id in &["goose", "claude", "codex", "buzz-agent", "antigravity"] {
             assert!(check_id_collision(id).is_err(), "{id} should be rejected");
         }
         // Tier-2 preset IDs must also be reserved (derived from PRESET_HARNESSES).
@@ -546,6 +546,44 @@ mod tests {
         }
     }
 
+    #[test]
+    fn check_id_collision_rejects_antigravity_case_insensitively() {
+        assert!(check_id_collision("antigravity").is_err());
+        assert!(check_id_collision("AntiGravity").is_err());
+        assert!(check_id_collision("ANTIGRAVITY").is_err());
+        assert!(check_id_collision("aNtiGravity").is_err());
+        assert!(check_id_collision("custom-antigravity").is_ok());
+        assert!(check_id_collision("antigravity-custom").is_ok());
+    }
+
+    #[test]
+    fn load_custom_harnesses_drops_file_shadowing_antigravity() {
+        let dir = tempfile::tempdir().unwrap();
+        std::fs::write(
+            dir.path().join("antigravity.json"),
+            r#"{"id":"antigravity","label":"Shadow Antigravity","command":"fake-agy"}"#,
+        )
+        .unwrap();
+        assert!(
+            load_custom_harnesses(dir.path()).is_empty(),
+            "loader must drop a custom harness file with id 'antigravity'"
+        );
+    }
+
+    #[test]
+    fn load_custom_harnesses_drops_file_shadowing_antigravity_mixed_case() {
+        let dir = tempfile::tempdir().unwrap();
+        std::fs::write(
+            dir.path().join("custom.json"),
+            r#"{"id":"AntiGravity","label":"Shadow Antigravity","command":"fake-agy"}"#,
+        )
+        .unwrap();
+        assert!(
+            load_custom_harnesses(dir.path()).is_empty(),
+            "loader must drop a custom harness file with id 'AntiGravity'"
+        );
+    }
+
     #[test]
     fn unknown_id_passes_collision_check() {
         assert!(check_id_collision("my-custom-agent").is_ok());

@@ -33,6 +33,8 @@ const CLAUDE_CODE_AVATAR_URL: &str = "https://anthropic.gallerycdn.vsassets.io/e
 const CODEX_AVATAR_URL: &str = "https://openai.gallerycdn.vsassets.io/extensions/openai/chatgpt/26.5313.41514/1773706730621/Microsoft.VisualStudio.Services.Icons.Default";
 const BUZZ_AGENT_AVATAR_URL: &str =
     "https://raw.githubusercontent.com/block/buzz/refs/heads/main/crates/buzz-agent/buzz-agent.png";
+const ANTIGRAVITY_AVATAR_URL: &str =
+    "https://raw.githubusercontent.com/block/buzz/refs/heads/main/desktop/public/harness-logos/antigravity.svg";
 fn common_binary_paths() -> &'static [PathBuf] {
     static PATHS: OnceLock<Vec<PathBuf>> = OnceLock::new();
     PATHS.get_or_init(|| {
@@ -219,6 +221,39 @@ const KNOWN_ACP_RUNTIMES: &[KnownAcpRuntime] = &[
         login_hint: None,
         auth_probe_args: None,
     },
+    KnownAcpRuntime {
+        id: "antigravity",
+        label: "Antigravity",
+        commands: &["agy"],
+        aliases: &["antigravity", "google-antigravity"],
+        avatar_url: ANTIGRAVITY_AVATAR_URL,
+        mcp_command: None,
+        mcp_hooks: false,
+        underlying_cli: None,
+        cli_install_commands: &[],
+        cli_install_commands_windows: &[],
+        adapter_install_commands: &[],
+        cli_install_instructions_url: "https://antigravity.google.com",
+        adapter_install_instructions_url: "",
+        cli_install_hint: "Buzz expects agy on PATH (install agy via Google Antigravity). No managed download is bundled.",
+        adapter_install_hint: "",
+        skill_dir: Some(".antigravity/skills"),
+        supports_acp_model_switching: false,
+        model_env_var: None,
+        provider_env_var: None,
+        provider_locked: true,
+        default_env: &[],
+        config_file_path: None,
+        config_file_format: None,
+        supports_acp_native_config: false,
+        thinking_env_var: None,
+        max_tokens_env_var: None,
+        context_limit_env_var: None,
+        max_rounds_env_var: None,
+        required_normalized_fields: &[],
+        login_hint: Some("Authenticate with Google to use Antigravity."),
+        auth_probe_args: None,
+    },
 ];
 
 /// Skill discovery directories declared by known runtimes.
@@ -254,7 +289,8 @@ pub(crate) fn normalize_command_identity(command: &str) -> String {
             _ => character.to_ascii_lowercase(),
         })
         .collect::<String>();
-    let lower = lower.strip_suffix(".exe").unwrap_or(&lower).to_string();
+    let lower = lower.strip_suffix(".exe").unwrap_or(&lower);
+    let lower = lower.strip_suffix(".par").unwrap_or(lower).to_string();
 
     if let Some(suffix) = std::env::consts::EXE_SUFFIX.strip_prefix('.') {
         return lower
@@ -448,9 +484,10 @@ pub fn try_record_agent_command(
     Ok(default_agent_command())
 }
 
-fn default_agent_args(command: &str) -> Option<Vec<String>> {
+pub(crate) fn default_agent_args(command: &str) -> Option<Vec<String>> {
     match normalize_command_identity(command).as_str() {
         "goose" => Some(vec!["acp".to_string()]),
+        "antigravity" | "google-antigravity" | "agy" | "agy-acp-server" => Some(Vec::new()),
         "codex" | "codex-acp" | "claude-agent-acp" | "claude-code-acp" | "claude-code"
         | "claudecode" | "buzz-agent" => Some(Vec::new()),
         _ => None,
@@ -472,7 +509,9 @@ pub fn normalize_agent_args(command: &str, agent_args: Vec<String>) -> Vec<Strin
         return default_args;
     }
 
-    if normalized.len() == 1 && normalized[0].eq_ignore_ascii_case("acp") && default_args.is_empty()
+    if normalized.len() == 1
+        && normalized[0].eq_ignore_ascii_case("acp")
+        && normalize_command_identity(command) != "goose"
     {
         return default_args;
     }

@@ -123,4 +123,18 @@ mod tests {
         assert!(codex.adapter_install_instructions_url.contains("codex-acp"));
         assert!(codex.cli_install_hint.contains("Codex CLI"));
     }
+
+    #[test]
+    fn vendor_metadata_antigravity_contract() {
+        let agy = known_acp_runtime_exact("antigravity").unwrap();
+        assert_eq!(
+            agy.cli_install_instructions_url,
+            "https://antigravity.google.com"
+        );
+        assert!(agy.adapter_install_instructions_url.is_empty());
+        assert!(agy.cli_install_hint.contains("Google Antigravity"));
+        assert!(agy.cli_install_commands.is_empty());
+        assert!(agy.adapter_install_commands.is_empty());
+        assert_eq!(agy.skill_dir, Some(".antigravity/skills"));
+    }
 }