Add Google Antigravity MCP client page

[robertjamesprior]

Summary

Adds reference/mcp-server/clients/antigravity.mdx and its docs.json nav entry, and lists the new antigravity target on the CLI reference page. Antigravity had no setup page, so anyone connecting it to the Kernel MCP server had to work the config shape out themselves.

Three things the page pins down:

• serverUrl, not url. Antigravity ignores url and httpUrl for remote servers. Config lives in mcp_config.json — ~/.gemini/config/mcp_config.json globally, .agents/mcp_config.json per workspace.
• The OAuth flow has a paste-back step. Authenticate from Customizations in agent settings, then copy the authorization code out of the browser and submit it in the panel. That's unusual enough to be worth spelling out.
• An API-key fallback. Antigravity can finish OAuth and still send initialize without the bearer token, returning 401 Unauthorized (antigravity-cli#25, open since May). The headers form sidesteps it.

Structured to match fx.mdx, which is the existing precedent for a client whose OAuth path needs a documented workaround — CLI install first, manual config second, API-key workaround last.

Merge order

This documents kernel mcp install --target antigravity, which is added in kernel/cli#265. Land that first, otherwise this page advertises a target the shipped CLI rejects.

Validation

• mint broken-links: passes.
• docs.json parses, and the new nav entry resolves to a file that exists.
• API-key path verified live: POST https://mcp.onkernel.com/mcp with Authorization: Bearer <key> returns 200 and a valid initialize result.
• The documented CLI output matches what the kernel/cli branch actually writes, checked by running the built binary against a throwaway HOME.
• Setup steps, config paths, and the token-store location are taken from Antigravity's own MCP documentation. I did not run the flow inside Antigravity itself, so the UI clickpath is documented rather than reproduced.

🤖 Generated with Claude Code

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Note

Low Risk
Documentation-only changes with no runtime or auth logic modifications in this repo.

Overview
Adds documentation for connecting Google Antigravity to the Kernel MCP server, including a new Connect Your Client nav entry and CLI coverage for kernel mcp install --target antigravity.

The Antigravity page documents Antigravity-specific setup: remote MCP config uses serverUrl (not url/httpUrl) in mcp_config.json, the OAuth path with paste-back of the authorization code, and an API-key header workaround for a known issue where OAuth can succeed but initialize still returns 401 without a bearer token.

The CLI MCP reference lists antigravity as a supported target and notes that install writes HTTP config keyed on serverUrl.

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[mintlify]

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Project	Status	Preview	Updated
Kernel	🟢 Ready	View Preview	Sep 20, 2026, 8:21 AM

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[cursor]

Risk assessment: Very Low

Re-evaluated this PR from the diff at 23f3c1ecccc4737baf084be6ff275139bf375032 (same commit as the existing approval). Risk is unchanged.

This is documentation-only. The diff adds a Mintlify client page (reference/mcp-server/clients/antigravity.mdx), one docs.json nav entry, and two lines on the CLI MCP reference listing the antigravity install target. No application code, auth, billing, permissions, or infrastructure is modified.

Scope

• 3 files, +62 / −0
• New page follows the existing MCP client-doc pattern (CLI install, manual config, API-key workaround)
• No CODEOWNERS file in the repo

Why Very Low

• Small, isolated docs surface with no production logic or shared-system blast radius
• Config examples use placeholders (YOUR_KERNEL_API_KEY), not credentials
• No prompt/instruction-file changes that would alter model behavior

Existing approval stands. Not re-approving (same commit, risk did not increase).

  

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