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The Best Free MCP Servers for Google Antigravity in 2026

Compare the best free MCP servers for Google Antigravity, with installation steps, credentials, security checks, costs, and a ScreenshotNeo option.

By the ScreenshotNeo team1 October 20267 min read

Start with the official Antigravity MCP Store. It has the lowest-friction setup and documented authentication. Use Google Cloud remote MCP servers when your agent needs Google-managed data or infrastructure context. Use Google-maintained repositories for specialized domains, and review community servers carefully before granting access.

“Free” usually means the connector or server code has no separate fee. Your Google Cloud project, SaaS account, API quota, or provider usage can still cost money.

What MCP does in Google Antigravity

Model Context Protocol (MCP) gives Antigravity agents and editors a standard way to call local tools, databases, file parsers, and remote APIs. Antigravity 2.0 includes an Installed MCP Servers section and a searchable MCP Store.

Antigravity supports local stdio processes and remote MCP configurations. Global configuration is stored at ~/.gemini/config/mcp_config.json; workspace configuration is stored at .agents/mcp_config.json. Store-installed integrations can be configured in the IDE, while custom servers can be added as raw JSON.

Best free MCP servers and integrations

1. Official Antigravity MCP Store integrations

Best default choice. The Store provides searchable, in-product installation and supported authentication. Documented integrations include AlloyDB, BigQuery, Bigtable Admin, and ClickHouse, alongside services for storage, productivity, and developer workflows.

  • Use it when: you want the quickest setup and a documented Antigravity path.
  • Credentials: authentication depends on the connector; an account, OAuth consent, or cloud permissions may be required.
  • Cost: the integration can be free while the underlying service charges for storage, queries, requests, or quota.

2. Google Cloud remote MCP servers

Google Cloud documents remote MCP connections using Application Default Credentials (ADC) or OAuth client credentials. Remote entries use serverUrl; custom headers can carry bearer tokens when a server requires them.

  • Use it when: your agent needs Google Cloud data, deployment context, or observability services.
  • Transport: remote Streamable HTTP or SSE.
  • Watch: IAM permissions, project quotas, and service usage still apply even when the MCP endpoint has no connector fee.

3. Google-maintained MCP repositories

Google’s MCP repository and Google Cloud’s HCLS MCP repository publish server code and deployment guidance. They suit teams that need inspectable source, self-hosting, or specialized domains.

The HCLS repository documents Antigravity configuration and notes that umls_mcp requires a free UMLS API key. Self-hosting adds work: you must install dependencies, manage secrets, patch vulnerabilities, and keep the process available.

4. Kio-pon/antigravity-mcp (community)

This community server dispatches background subagent jobs to Antigravity IDE’s local agent engine. Its repository says IDE dispatch needs no API key, supports the 2026-07-28 MCP specification and earlier revisions, and was verified against Antigravity IDE v1.107.0 on Linux. macOS and Windows support is described as implemented but not fully verified on real hardware.

Treat it as a community option. Check recent commits and releases, inspect its tools and permissions, and test it in a restricted workspace before enabling broad access.

Install an MCP server in Antigravity

  1. Open the MCP Store: in Antigravity 2.0, open the MCP section and search for the integration you need.
  2. Install and authenticate: follow the connector’s OAuth, ADC, or API-key flow. Confirm the provider project and account are the intended ones.
  3. Review tools: inspect every exposed tool and whether it can write, delete, deploy, or send data.
  4. Test with a read-only request: ask the agent to list a resource or inspect metadata before attempting a mutation.
  5. For a custom server: add a local or remote entry to the global or workspace configuration file, then restart or reload MCP servers.

Configuration examples

Local stdio server

{
  "mcpServers": {
    "example-local": {
      "command": "npx",
      "args": ["-y", "@example/mcp-server"],
      "env": {
        "EXAMPLE_TOKEN": "replace-me"
      },
      "cwd": "/absolute/path/to/project"
    }
  }
}

Use command for the executable. Add args, environment variables in env, and an optional working directory in cwd. Keep secrets out of source control and prefer your operating system’s secret store or injected environment variables.

Remote Streamable HTTP or SSE server

{
  "mcpServers": {
    "example-remote": {
      "serverUrl": "https://server.example/mcp",
      "headers": {
        "Authorization": "Bearer ${EXAMPLE_TOKEN}"
      },
      "disabled": false,
      "disabledTools": ["delete_resource"]
    }
  }
}

Use serverUrl for remote declarations. Optional fields include headers, OAuth settings, disabled, and disabledTools. Current Antigravity documentation does not support legacy url or httpUrl fields for remote declarations.

Gemini API Antigravity agent registration

{
  "type": "mcp_server",
  "name": "example_remote",
  "url": "https://server.example/mcp",
  "headers": {
    "Authorization": "Bearer ${EXAMPLE_TOKEN}"
  },
  "allowed_tools": ["list_resources", "get_resource"]
}

The server name must be strictly lowercase. Use allowed_tools to expose only the operations the agent needs.

Credentials, quotas, and the real cost of “free”

Server type Typical credential Possible charges
Store integration OAuth, cloud login, or provider key Underlying SaaS or cloud usage
Google Cloud remote ADC or OAuth client credentials Project services, requests, storage, and quota
Google-maintained repository Depends on server; UMLS needs a free API key Hosting and upstream service usage
Community server None, API key, or custom token Hosting, provider APIs, and maintenance time

Before installation, identify the billing account, quota owner, token scopes, and any write operations. A connector with no license fee is not automatically cost-free.

Safety checklist for Antigravity MCP servers

  • Prefer official Store integrations or Google-maintained source for sensitive work.
  • Read the repository, package manifest, install script, and release history.
  • Run community servers in a dedicated environment with minimal filesystem and network access.
  • Use separate credentials with the smallest practical scope.
  • Keep destructive tools disabled until you need them.
  • Antigravity places unconfigured MCP tools in Ask mode by default. Keep approval prompts for tools that write, deploy, delete, or transmit data.
  • Policies can match one tool with mcp(server/tool), every tool on a server with mcp(server/*), or all MCP tools with mcp(*).

Choosing the right server

Question What to check
Does it cover your task? Database, files, source control, cloud, browser, or domain knowledge
How does it connect? Local stdio versus remote HTTP/SSE
How are secrets handled? No key, OAuth, ADC, API key, or bearer header
What can it change? Read-only tools, writes, deployments, deletes, and tool restrictions
Will it stay compatible? Official support, repository activity, release compatibility, and issue response
What will it cost? Connector fee, provider account, quota, API usage, and hosting

Troubleshooting

Server does not appear

Check that the JSON file is in ~/.gemini/config/mcp_config.json or .agents/mcp_config.json, that the JSON parses, and that the server name is unique. Restart or reload MCP servers after editing.

“Unsupported field” or remote connection fails

Replace legacy url or httpUrl with serverUrl. Confirm the endpoint supports the declared Streamable HTTP or SSE transport and that outbound network access is allowed.

401 or 403 responses

Refresh OAuth or ADC credentials, verify the active account and project, and check IAM roles or token scopes. For custom authentication, confirm the exact header name and bearer-token format.

Local process exits immediately

Run the command manually in a terminal, verify the runtime is on Antigravity’s PATH, install dependencies, and check the configured cwd. Put required environment variables in env.

A tool is missing

Inspect disabledTools, allowed_tools, and policy rules. The server may expose a different tool name or the tool may be disabled by default.

Actions are blocked by approval prompts

This is expected Ask-mode behavior. Approve the individual call, or create a narrowly scoped policy for the specific server and tool after reviewing its effect.

Performance and reliability

Local stdio avoids network round trips but depends on the machine’s runtime, dependencies, and process health. Remote servers centralize maintenance and can serve multiple workspaces, but add network latency, authentication expiry, endpoint availability, and quota limits.

For reliable agent runs, keep tool calls small, restrict result size, use read-only tools for exploration, and retry only idempotent operations. Log the server name, tool, request ID, and provider error without recording secrets. Pin package versions for local servers and monitor repository changes before upgrading.

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FAQ

Are Google Cloud MCP servers free?

The connector or server may have no separate fee, but Google Cloud services, quotas, storage, and requests can still be billed.

Which Antigravity MCP servers need an API key?

It depends on the server. Google Cloud commonly uses ADC or OAuth; umls_mcp requires a free UMLS API key; the community Kio-pon server says IDE dispatch needs no API key.

Should I use a local or remote server?

Choose local stdio for machine-local files and low network dependence. Choose remote HTTP or SSE for centrally managed services and shared infrastructure context.

What is the safest first installation?

Use an official Antigravity MCP Store integration, keep tools in Ask mode, grant the smallest credential scope, and test read-only operations first.

Can Antigravity restrict individual tools?

Yes. Use disabledTools, allowed_tools, and MCP policy patterns such as mcp(server/tool).

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