feat: Add Google Anti-Gravity (IDX) Support

.github/workflows/scripts/create-github-release.sh

@@ -42,6 +42,8 @@ gh release create "$VERSION" \
   .genreleases/spec-kit-template-codebuddy-ps-"$VERSION".zip \
   .genreleases/spec-kit-template-amp-sh-"$VERSION".zip \
   .genreleases/spec-kit-template-amp-ps-"$VERSION".zip \
+  .genreleases/spec-kit-template-antigravity-sh-"$VERSION".zip \
+  .genreleases/spec-kit-template-antigravity-ps-"$VERSION".zip \
   .genreleases/spec-kit-template-q-sh-"$VERSION".zip \
   .genreleases/spec-kit-template-q-ps-"$VERSION".zip \
   --title "Spec Kit Plus Templates - $VERSION_NO_V" \

.github/workflows/scripts/create-release-packages.sh

@@ -200,6 +200,7 @@ build_variant() {
       codebuddy) agent_name="CodeBuddy" ;;
       amp) agent_name="AWS Amplify AI" ;;
       q) agent_name="Amazon Q Developer CLI" ;;
+      antigravity) agent_name="Google Anti-Gravity" ;;
       *) agent_name="$agent" ;;
     esac
 
@@ -274,6 +275,11 @@ This file is generated during init for the selected agent.
         echo "$full_content" > "$base_dir/AMP.md"
         echo "Generated AMP.md"
         ;;
+      antigravity)
+        mkdir -p "$base_dir/.idx"
+        echo "$full_content" > "$base_dir/.idx/specify-rules.md"
+        echo "Generated .idx/specify-rules.md"
+        ;;
     esac
   }
 
@@ -337,13 +343,21 @@ This file is generated during init for the selected agent.
       mkdir -p "$base_dir/.amazonq/prompts"
       generate_commands q md "\$ARGUMENTS" "$base_dir/.amazonq/prompts" "$script"
       generate_agent_rules q "$base_dir" ;;
+    antigravity)
+      mkdir -p "$base_dir/.idx"
+      generate_commands antigravity md "\$ARGUMENTS" "$base_dir/.idx" "$script"
+      # Copy MCP server and configuration templates
+      cp templates/antigravity/specify_mcp.py "$base_dir/.idx/" 2>/dev/null || true
+      cp templates/antigravity/dev.nix "$base_dir/.idx/" 2>/dev/null || true
+      cp templates/antigravity/mcp.json "$base_dir/.idx/" 2>/dev/null || true
+      generate_agent_rules antigravity "$base_dir" ;;
   esac
   ( cd "$base_dir" && zip -r "../spec-kit-template-${agent}-${script}-${NEW_VERSION}.zip" . )
   echo "Created $GENRELEASES_DIR/spec-kit-template-${agent}-${script}-${NEW_VERSION}.zip"
 }
 
 # Determine agent list
-ALL_AGENTS=(claude gemini copilot cursor-agent qwen opencode windsurf codex kilocode auggie roo codebuddy amp q)
+ALL_AGENTS=(claude gemini copilot cursor-agent qwen opencode windsurf codex kilocode auggie roo codebuddy amp q antigravity)
 ALL_SCRIPTS=(sh ps)
 
 norm_list() {

AGENTS.md

@@ -119,6 +119,7 @@ Specify supports multiple AI agents by generating agent-specific command files a
 | **CodeBuddy CLI** | `.codebuddy/commands/` | Markdown | `codebuddy` | CodeBuddy CLI |
 | **Amazon Q Developer CLI** | `.amazonq/prompts/` | Markdown | `q` | Amazon Q Developer CLI |
 | **Amp** | `.agents/commands/` | Markdown | `amp` | Amp CLI |
+| **Google Anti-Gravity** | `.idx/` | Python (MCP) | N/A (IDE-based) | Google IDX with MCP server |
 
 ### Step-by-Step Integration Guide
 

CHANGELOG.md

@@ -7,6 +7,23 @@ All notable changes to the Specify CLI and templates are documented here.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+
+- **Google Anti-Gravity Agent Support**
+  - Added official support for Google Anti-Gravity IDE agent with Google IDX integration
+  - Implemented split-config approach for Google IDX/Firebase Studio compatibility:
+    - `.idx/dev.nix` - Runtime environment setup (Python 3.11, uv, mcp library)
+    - `.idx/mcp.json` - MCP server registration for Google IDX
+    - `.idx/specify_mcp.py` - FastMCP server with specify and plan prompts
+  - Agent configuration in `src/specify_cli/__init__.py` with folder `.idx/`
+  - Build scripts updated to generate antigravity release packages with template copying
+  - Agent context update scripts (bash and PowerShell) support antigravity
+  - Template files created in `templates/antigravity/`
+  - Documentation updated with Anti-Gravity in supported agents table
+  - Slash commands work via MCP server integration in Google IDX
+
 ## [0.0.17] - 2025-10-28
 
 ### Changed

scripts/bash/update-agent-context.sh

@@ -72,6 +72,7 @@ ROO_FILE="$REPO_ROOT/.roo/rules/specify-rules.md"
 CODEBUDDY_FILE="$REPO_ROOT/CODEBUDDY.md"
 AMP_FILE="$REPO_ROOT/AGENTS.md"
 Q_FILE="$REPO_ROOT/AGENTS.md"
+ANTIGRAVITY_FILE="$REPO_ROOT/.idx/specify_mcp.py"
 
 # Template file
 TEMPLATE_FILE="$REPO_ROOT/.specify/templates/agent-file-template.md"
@@ -621,9 +622,12 @@ update_specific_agent() {
         q)
             update_agent_file "$Q_FILE" "Amazon Q Developer CLI"
             ;;
+        antigravity)
+            update_agent_file "$ANTIGRAVITY_FILE" "Google Anti-Gravity"
+            ;;
         *)
             log_error "Unknown agent type '$agent_type'"
-            log_error "Expected: claude|gemini|copilot|cursor-agent|qwen|opencode|codex|windsurf|kilocode|auggie|roo|amp|q"
+            log_error "Expected: claude|gemini|copilot|cursor-agent|qwen|opencode|codex|windsurf|kilocode|auggie|roo|amp|q|antigravity"
             exit 1
             ;;
     esac
@@ -693,6 +697,11 @@ update_all_existing_agents() {
         found_agent=true
     fi
 
+    if [[ -f "$ANTIGRAVITY_FILE" ]]; then
+        update_agent_file "$ANTIGRAVITY_FILE" "Google Anti-Gravity"
+        found_agent=true
+    fi
+
     # If no agent files exist, create a default Claude file
     if [[ "$found_agent" == false ]]; then
         log_info "No existing agent files found, creating default Claude file..."
@@ -717,7 +726,7 @@ print_summary() {
 
     echo
 
-    log_info "Usage: $0 [claude|gemini|copilot|cursor-agent|qwen|opencode|codex|windsurf|kilocode|auggie|codebuddy|q]"
+    log_info "Usage: $0 [claude|gemini|copilot|cursor-agent|qwen|opencode|codex|windsurf|kilocode|auggie|codebuddy|q|antigravity]"
 }
 
 #==============================================================================

scripts/powershell/update-agent-context.ps1

@@ -25,7 +25,7 @@ Relies on common helper functions in common.ps1
 #>
 param(
     [Parameter(Position=0)]
-    [ValidateSet('claude','gemini','copilot','cursor-agent','qwen','opencode','codex','windsurf','kilocode','auggie','roo','codebuddy','amp','q')]
+    [ValidateSet('claude','gemini','copilot','cursor-agent','qwen','opencode','codex','windsurf','kilocode','auggie','roo','codebuddy','amp','q','antigravity')]
     [string]$AgentType
 )
 
@@ -57,6 +57,7 @@ $ROO_FILE      = Join-Path $REPO_ROOT '.roo/rules/specify-rules.md'
 $CODEBUDDY_FILE = Join-Path $REPO_ROOT 'CODEBUDDY.md'
 $AMP_FILE      = Join-Path $REPO_ROOT 'AGENTS.md'
 $Q_FILE        = Join-Path $REPO_ROOT 'AGENTS.md'
+$ANTIGRAVITY_FILE = Join-Path $REPO_ROOT '.idx/specify_mcp.py'
 
 $TEMPLATE_FILE = Join-Path $REPO_ROOT '.specify/templates/agent-file-template.md'
 
@@ -382,7 +383,8 @@ function Update-SpecificAgent {
         'codebuddy' { Update-AgentFile -TargetFile $CODEBUDDY_FILE -AgentName 'CodeBuddy CLI' }
         'amp'      { Update-AgentFile -TargetFile $AMP_FILE      -AgentName 'Amp' }
         'q'        { Update-AgentFile -TargetFile $Q_FILE        -AgentName 'Amazon Q Developer CLI' }
-        default { Write-Err "Unknown agent type '$Type'"; Write-Err 'Expected: claude|gemini|copilot|cursor-agent|qwen|opencode|codex|windsurf|kilocode|auggie|roo|codebuddy|amp|q'; return $false }
+        'antigravity' { Update-AgentFile -TargetFile $ANTIGRAVITY_FILE -AgentName 'Google Anti-Gravity' }
+        default { Write-Err "Unknown agent type '$Type'"; Write-Err 'Expected: claude|gemini|copilot|cursor-agent|qwen|opencode|codex|windsurf|kilocode|auggie|roo|codebuddy|amp|q|antigravity'; return $false }
     }
 }
 
@@ -401,6 +403,7 @@ function Update-AllExistingAgents {
     if (Test-Path $ROO_FILE)      { if (-not (Update-AgentFile -TargetFile $ROO_FILE      -AgentName 'Roo Code')) { $ok = $false }; $found = $true }
     if (Test-Path $CODEBUDDY_FILE) { if (-not (Update-AgentFile -TargetFile $CODEBUDDY_FILE -AgentName 'CodeBuddy CLI')) { $ok = $false }; $found = $true }
     if (Test-Path $Q_FILE)        { if (-not (Update-AgentFile -TargetFile $Q_FILE        -AgentName 'Amazon Q Developer CLI')) { $ok = $false }; $found = $true }
+    if (Test-Path $ANTIGRAVITY_FILE) { if (-not (Update-AgentFile -TargetFile $ANTIGRAVITY_FILE -AgentName 'Google Anti-Gravity')) { $ok = $false }; $found = $true }
     if (-not $found) {
         Write-Info 'No existing agent files found, creating default Claude file...'
         if (-not (Update-AgentFile -TargetFile $CLAUDE_FILE -AgentName 'Claude Code')) { $ok = $false }
@@ -415,7 +418,7 @@ function Print-Summary {
     if ($NEW_FRAMEWORK) { Write-Host "  - Added framework: $NEW_FRAMEWORK" }
     if ($NEW_DB -and $NEW_DB -ne 'N/A') { Write-Host "  - Added database: $NEW_DB" }
     Write-Host ''
-    Write-Info 'Usage: ./update-agent-context.ps1 [-AgentType claude|gemini|copilot|cursor-agent|qwen|opencode|codex|windsurf|kilocode|auggie|roo|codebuddy|amp|q]'
+    Write-Info 'Usage: ./update-agent-context.ps1 [-AgentType claude|gemini|copilot|cursor-agent|qwen|opencode|codex|windsurf|kilocode|auggie|roo|codebuddy|amp|q|antigravity]'
 }
 
 function Main {

src/specify_cli/__init__.py

@@ -151,6 +151,12 @@ def _github_auth_headers(cli_token: str | None = None) -> dict:
         "install_url": "https://ampcode.com/manual#install",
         "requires_cli": True,
     },
+    "antigravity": {
+        "name": "Google Anti-Gravity",
+        "folder": ".idx/",
+        "install_url": None,
+        "requires_cli": False,
+    },
 }
 
 SCRIPT_TYPE_CHOICES = {"sh": "POSIX Shell (bash/zsh)", "ps": "PowerShell"}
@@ -580,6 +586,7 @@ def deep_merge(base: dict, update: dict) -> dict:
 def download_template_from_github(ai_assistant: str, download_dir: Path, *, script_type: str = "sh", verbose: bool = True, show_progress: bool = True, client: httpx.Client = None, debug: bool = False, github_token: str = None) -> Tuple[Path, dict]:
     repo_owner = "github"
     repo_name = "spec-kit"
+
     if client is None:
         client = httpx.Client(verify=ssl_context)
 

src/specifyplus_cli/__init__.py

@@ -151,6 +151,12 @@ def _github_auth_headers(cli_token: str | None = None) -> dict:
         "install_url": "https://ampcode.com/manual#install",
         "requires_cli": True,
     },
+    "antigravity": {
+        "name": "Google Anti-Gravity",
+        "folder": ".idx/",
+        "install_url": None,
+        "requires_cli": False,
+    },
 }
 
 SCRIPT_TYPE_CHOICES = {"sh": "POSIX Shell (bash/zsh)", "ps": "PowerShell"}
@@ -584,6 +590,7 @@ def deep_merge(base: dict, update: dict) -> dict:
 def download_template_from_github(ai_assistant: str, download_dir: Path, *, script_type: str = "sh", verbose: bool = True, show_progress: bool = True, client: httpx.Client = None, debug: bool = False, github_token: str = None) -> Tuple[Path, dict]:
     repo_owner = "panaversity"
     repo_name = "spec-kit-plus"
+
     if client is None:
         client = httpx.Client(verify=ssl_context)
 

templates/antigravity/dev.nix

@@ -0,0 +1,9 @@
+{ pkgs, ... }: {
+  packages = [ 
+    pkgs.python311
+    pkgs.uv
+  ];
+  idx.workspace.onCreate = {
+    install = "pip install mcp[cli]";
+  };
+}

templates/antigravity/mcp.json

@@ -0,0 +1,8 @@
+{
+  "mcpServers": {
+    "spec-kit": {
+      "command": "python",
+      "args": [".idx/specify_mcp.py"]
+    }
+  }
+}

templates/antigravity/specify_mcp.py

@@ -0,0 +1,15 @@
+from mcp.server.fastmcp import FastMCP
+mcp = FastMCP("Spec-Kit")
+
+@mcp.prompt()
+def specify(goal: str):
+    """Start the Spec-Driven Development process."""
+    return f"Role: AI Architect. Goal: {goal}. Create a SPEC.md file."
+
+@mcp.prompt()
+def plan(spec_content: str):
+    """Generate a plan from the spec."""
+    return f"Read this spec: {spec_content}. Create a PLAN.md."
+
+if __name__ == "__main__":
+    mcp.run()