TheBushidoCollective · jwaldrip · Feb 9, 2026 · Mar 23, 2026
diff --git a/.claude-plugin/marketplace.json b/.claude-plugin/marketplace.json
@@ -951,6 +951,21 @@
       "category": "Pattern",
       "keywords": ["oop", "object-oriented", "design-patterns", "encapsulation"]
     },
+    {
+      "name": "antigravity",
+      "description": "Bridge plugin that enables Han's hook ecosystem (validation, skills, disciplines) to work with Google Antigravity IDE via MCP server.",
+      "source": "./plugins/bridges/antigravity",
+      "category": "Integration",
+      "keywords": [
+        "antigravity",
+        "google",
+        "bridge",
+        "mcp",
+        "hooks",
+        "validation",
+        "skills"
+      ]
+    },
     {
       "name": "opencode",
       "description": "Bridge plugin that enables Han's hook ecosystem (validation, context injection, orchestration) to work with OpenCode by translating OpenCode events into Claude Code hook invocations.",
@@ -2484,6 +2499,21 @@
         "server"
       ]
     },
+    {
+      "name": "hashi-antigravity",
+      "description": "Bridge plugin that enables Han's hook ecosystem (validation, skills, disciplines) to work with Google Antigravity IDE via MCP server.",
+      "source": "./plugins/bridges/antigravity",
+      "category": "Integration",
+      "keywords": [
+        "antigravity",
+        "google",
+        "bridge",
+        "mcp",
+        "hooks",
+        "validation",
+        "skills"
+      ]
+    },
     {
       "name": "hashi-opencode",
       "description": "Bridge plugin that enables Han's hook ecosystem (validation, context injection, orchestration) to work with OpenCode by translating OpenCode events into Claude Code hook invocations.",

diff --git a/packages/han/lib/plugin-aliases.ts b/packages/han/lib/plugin-aliases.ts
@@ -131,6 +131,7 @@ export const PLUGIN_ALIASES: Record<string, string> = {
   blueprints: 'tools/blueprints',
 
   // bridges
+  'hashi-antigravity': 'bridges/antigravity',
   'hashi-opencode': 'bridges/opencode',
 
   // services

diff --git a/plugins/bridges/antigravity/.claude-plugin/plugin.json b/plugins/bridges/antigravity/.claude-plugin/plugin.json
@@ -0,0 +1,21 @@
+{
+  "name": "antigravity",
+  "version": "0.1.0",
+  "description": "Bridge plugin that enables Han's hook ecosystem (validation, skills, disciplines) to work with Google Antigravity IDE via MCP server.",
+  "author": {
+    "name": "The Bushido Collective",
+    "url": "https://thebushido.co"
+  },
+  "homepage": "https://github.com/thebushidocollective/han",
+  "repository": "https://github.com/thebushidocollective/han",
+  "license": "Apache-2.0",
+  "keywords": [
+    "antigravity",
+    "google",
+    "bridge",
+    "mcp",
+    "hooks",
+    "validation",
+    "skills"
+  ]
+}
diff --git a/plugins/bridges/antigravity/README.md b/plugins/bridges/antigravity/README.md
@@ -0,0 +1,188 @@
+# Han Bridge for Google Antigravity
+
+MCP server that brings Han's full plugin ecosystem to [Google Antigravity](https://antigravity.google/) IDE -- 400+ skills, 25 agent disciplines, and on-demand validation hooks.
+
+## What This Does
+
+Han plugins define validation hooks, specialized skills, and agent disciplines that run during Claude Code sessions. This bridge makes the entire ecosystem work in Antigravity via MCP:
+
+1. **Skills** -- 400+ coding skills loadable on demand via `han_skills` tool
+2. **Disciplines** -- 25 agent personas (frontend, backend, SRE, security, etc.)
+3. **Validation** -- On-demand linting, type checking, and formatting via `han_validate`
+4. **Sync** -- Copy skills and rules to `.agent/` for native Antigravity discovery
+5. **Context** -- Current time and session state via `han_context`
+6. **Events** -- Unified JSONL logging with `provider: "antigravity"` for Browse UI
+
+## How It Works
+
+Unlike the OpenCode bridge (which hooks into JS plugin events), Antigravity doesn't have lifecycle hooks. Instead, this bridge runs as an MCP server and exposes Han's capabilities as tools:
+
+| Tool | Purpose | Replaces |
+|------|---------|----------|
+| `han_skills` | Browse/load 400+ skills | Native skill discovery |
+| `han_discipline` | Activate agent personas | System prompt injection |
+| `han_validate` | Run validation hooks | PostToolUse/Stop hooks |
+| `han_sync` | Sync skills/rules to .agent/ | SessionStart setup |
+| `han_context` | Get time + active discipline | UserPromptSubmit context |
+
+## Validation Modes
+
+### Per-File Validation (After Edits)
+
+```
+Agent: han_validate({ mode: "file", files: ["src/app.ts"], tool: "Edit" })
+→ Runs matching PostToolUse hooks (biome, eslint, tsc)
+→ Returns structured results with pass/fail per hook
+```
+
+### Project-Wide Validation (Before Finishing)
+
+```
+Agent: han_validate({ mode: "project" })
+→ Runs all Stop hooks (full project lint, typecheck, tests)
+→ Returns comprehensive validation summary
+```
+
+## Setup
+
+### Prerequisites
+
+Han plugins must be installed:
+
+```bash
+curl -fsSL https://han.guru/install.sh | bash
+han plugin install --auto
+```
+
+### Add MCP Server
+
+Add to `~/.gemini/antigravity/mcp_config.json`:
+
+```json
+{
+  "mcpServers": {
+    "han": {
+      "command": "npx",
+      "args": ["-y", "antigravity-han-mcp"]
+    }
+  }
+}
+```
+
+### Optional: Sync Skills Natively
+
+After setup, ask the agent to sync Han skills for native Antigravity discovery:
+
+```
+> Run han_sync to set up Han skills
+```
+
+This copies skills to `.agent/skills/` and creates `.agent/rules/han-guidelines.md`.
+
+## Architecture
+
+```
+Google Antigravity IDE
+  |
+  |-- mcp_config.json ─────────────────────> Han MCP Server
+  |     (stdio transport)                       |
+  |                                             |
+  |-- han_skills ──────────────────────────> Skill discovery
+  |     (LLM-callable tool)                    (list/search/load 400+ skills)
+  |                                             |
+  |-- han_discipline ──────────────────────> Agent disciplines
+  |     (LLM-callable tool)                    (activate/deactivate/list)
+  |                                             |
+  |-- han_validate ────────────────────────> Hook executor
+  |     (LLM-callable tool)                    |
+  |     mode="file"  ──> PostToolUse hooks     |
+  |     mode="project" ──> Stop hooks          |
+  |                                             |
+  |-- han_sync ────────────────────────────> Filesystem sync
+  |     (LLM-callable tool)                    |
+  |     skills → .agent/skills/                |
+  |     rules  → .agent/rules/                 |
+  |                                             |
+  |-- han_context ─────────────────────────> Session state
+  |     (LLM-callable tool)                    (time, discipline, stats)
+  |                                             |
+  |-- .agent/rules/han-guidelines.md ──────> Core guidelines
+  |     (native Antigravity rules)              (synced by han_sync)
+  |                                             |
+  |-- .agent/skills/han-*/SKILL.md ────────> Native skills
+  |     (native Antigravity skills)             (synced by han_sync)
+  |                                             |
+  |-- JSONL logger ────────────────────────> Event logging
+        (hook_run, hook_result)                 (Browse UI visibility)
+
+Bridge Internals:
+  index.ts         MCP server entry point (JSON-RPC over stdio)
+  discovery.ts     Read settings + marketplace + resolve plugin paths
+  skills.ts        Discover SKILL.md files from installed plugins
+  disciplines.ts   Discover discipline plugins, context builder
+  context.ts       Core guidelines + datetime for rules/context
+  sync.ts          Copy skills/rules to .agent/ directory
+  matcher.ts       Filter hooks by tool name, file globs, dirsWith
+  executor.ts      Spawn hook commands as parallel promises
+  formatter.ts     Structure results for MCP tool responses
+  events.ts        JSONL event logger (provider="antigravity")
+  cache.ts         Content-hash caching (SHA-256)
+```
+
+## Comparison with OpenCode Bridge
+
+| Feature | OpenCode Bridge | Antigravity Bridge |
+|---------|----------------|-------------------|
+| Integration | JS plugin API (events) | MCP server (tools) |
+| Validation trigger | Automatic (tool.execute.after) | On-demand (han_validate) |
+| Context injection | experimental.chat.system.transform | .agent/rules/ + han_context |
+| Skill discovery | han_skills tool | han_skills tool + .agent/skills/ sync |
+| Stop validation | Automatic (session.idle/stop) | On-demand (han_validate mode=project) |
+| Event logging | provider: "opencode" | provider: "antigravity" |
+
+## Remaining Gaps
+
+These are genuine platform limitations in Antigravity (as of Feb 2026):
+
+- **Automatic validation**: No lifecycle hooks, so validation requires explicit han_validate calls
+- **Permission denial**: Cannot block tool execution (no PreToolUse equivalent)
+- **Subagent hooks**: No SubagentStart/SubagentStop equivalent
+- **Session checkpoints**: Not available
+- **MCP tool events**: Cannot intercept MCP tool calls for validation
+
+## Skills
+
+The bridge gives the agent access to Han's full skill library (400+ skills across 95+ plugins). Two modes:
+
+- **MCP tool**: Agent calls `han_skills` to list/load skills on demand
+- **Native sync**: `han_sync` copies skills to `.agent/skills/` for Antigravity's native semantic matching
+
+## Disciplines
+
+25 agent personas available via `han_discipline`:
+
+- frontend, backend, api, architecture, mobile, database, security
+- infrastructure, sre, performance, accessibility, quality, documentation
+- and more
+
+When activated, the discipline's context is returned with each `han_context` call.
+
+## Event Logging
+
+Events are logged to `~/.han/antigravity/projects/{slug}/{sessionId}-han.jsonl` with `provider: "antigravity"`. The Han coordinator indexes these files and serves them through the Browse UI alongside Claude Code and OpenCode sessions.
+
+## Development
+
+```bash
+# From the han repo root
+cd plugins/bridges/antigravity
+
+# Run the MCP server directly
+bun src/index.ts --project-dir /path/to/project
+
+# The server reads JSON-RPC from stdin and writes to stdout
+```
+
+## License
+
+Apache-2.0
diff --git a/plugins/bridges/antigravity/han-plugin.yml b/plugins/bridges/antigravity/han-plugin.yml
@@ -0,0 +1,18 @@
+# Han plugin configuration for the Antigravity bridge.
+#
+# This plugin has no hooks of its own - it IS the bridge that enables
+# other Han plugins' hooks to run inside Google Antigravity IDE via MCP.
+#
+# Installation:
+#   1. Install Han plugins as usual: han plugin install --auto
+#   2. Add MCP server to ~/.gemini/antigravity/mcp_config.json:
+#      { "mcpServers": { "han": { "command": "npx", "args": ["-y", "antigravity-han-mcp"] } } }
+#   3. Han skills, disciplines, and validation are now available in Antigravity.
+
+hooks: {}
+
+learn_patterns:
+  - "antigravity"
+  - "anti.?gravity"
+  - "gemini"
+  - "agy"
diff --git a/plugins/bridges/antigravity/package.json b/plugins/bridges/antigravity/package.json
@@ -0,0 +1,42 @@
+{
+  "name": "antigravity-han-mcp",
+  "version": "0.1.0",
+  "description": "Han bridge for Google Antigravity - MCP server enabling Han's validation hooks, skills, and disciplines in Antigravity IDE",
+  "main": "src/index.ts",
+  "bin": "src/index.ts",
+  "type": "module",
+  "exports": {
+    ".": "./src/index.ts"
+  },
+  "files": [
+    "src/"
+  ],
+  "keywords": [
+    "antigravity",
+    "google-antigravity",
+    "mcp",
+    "mcp-server",
+    "han",
+    "claude-code",
+    "hooks",
+    "validation",
+    "linting",
+    "bridge",
+    "skills"
+  ],
+  "author": {
+    "name": "The Bushido Collective",
+    "url": "https://thebushido.co"
+  },
+  "license": "Apache-2.0",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/thebushidocollective/han",
+    "directory": "plugins/bridges/antigravity"
+  },
+  "homepage": "https://github.com/thebushidocollective/han/tree/main/plugins/bridges/antigravity",
+  "engines": {
+    "bun": ">=1.0.0",
+    "node": ">=18.0.0"
+  }
+}