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Connect HippoKit to Gemini (MCP)

The Gemini CLI is the supported way to connect HippoKit today: it reads remote MCP servers straight from its `settings.json`, so you point it at HippoKit's `/mcp` endpoint with a bearer token and you're live. This guide walks you through the connect flow, troubleshoots common issues, and answers the questions you'll have once HippoKit is live in Gemini.

GeminiEarly accessGemini Extensions support third-party MCP servers behind a feature flag that's rolling out across the consumer and Workspace apps.

The Gemini CLI is the supported way to connect HippoKit today: it reads remote MCP servers straight from its `settings.json`, so you point it at HippoKit's `/mcp` endpoint with a bearer token and you're live. The consumer Gemini app surfaces third-party tools as "Extensions" too, but that path is still rolling out behind a feature flag. Once connected via the CLI, ask Gemini to generate kits, list your library, and run quiz sessions — it calls the HippoKit tools automatically when the prompt makes sense.

What you can do once connected

Once Gemini can call HippoKit, you can ask it to:

  • Generate a study kit from any topic — flashcards, quiz, ebook, audience-themed slide deck, or AI-narrated audio. Each format obeys your HippoKit plan's quotas and feature gating.
  • List or search your library — the host can look up kits you've already generated and pull them into the conversation by topic, audience, or recency.
  • Run a review session — call get_due_cards and review_card to walk through the flashcards your spaced-repetition queue has surfaced for today.
  • Run a quiz — call start_quiz on any kit you own and answer each question conversationally.
  • Claim an anonymous preview — if a teammate sent you a preview kit URL, HippoKit can claim it into your library straight from the chat.

Connect HippoKit in 5 steps

Total time: about two minutes. You only need to do this once per device.

  1. Generate a HippoKit personal access token (PAT)

    Open https://hippokit.ai/settings/mcp while signed in to HippoKit. Click "Create token", name it (e.g. "Gemini CLI"), and copy the token — you only see it once. The token inherits your plan's daily quota and format gating.

  2. Open your Gemini CLI settings file

    Open `~/.gemini/settings.json` in your editor. If the file does not exist yet, create it with an empty JSON object `{}` — the Gemini CLI reads its MCP server list from here.

  3. Add HippoKit under `mcpServers`

    Add this under "mcpServers": "hippokit": { "httpUrl": "https://mcp.hippokit.ai/mcp", "headers": { "Authorization": "Bearer <your PAT>" } }. Replace <your PAT> with the token from step 1.

  4. Restart the Gemini CLI

    Restart the Gemini CLI (or run `/mcp refresh` inside an active session) so it picks up the new server. Run `/mcp` to confirm HippoKit appears in the list of connected servers.

  5. Test it

    Ask the CLI: "Generate flashcards on photosynthesis using HippoKit". The CLI should call HippoKit's `generate_kit` tool and return a shareable kit URL. If you see the kit, the connection is wired up correctly.

Quick reference

MCP server URL

https://mcp.hippokit.ai/mcp

Where PATs live

hippokit.ai/settings/mcp

Settings location

~/.gemini/settings.json (Gemini CLI)

Smoke-test prompt

“Generate flashcards on photosynthesis using HippoKit”

60-second video walkthrough

A short screencast of the Gemini connect flow is coming soon. For now, the five steps above are everything you need.

Troubleshooting

If something isn't working, walk this list top to bottom — common issues are listed first.

The host says HippoKit is unreachable or returns a 401.

Your PAT may have been revoked or rotated. Open https://hippokit.ai/settings/mcp, revoke any stale tokens, generate a fresh one, and update the host's saved credential.

The host refuses to call HippoKit tools mid-conversation.

Most hosts ask the user to approve each tool the first time it runs. Look for an inline approval prompt in the conversation transcript — sometimes it lives below the input box rather than inline with the assistant turn.

You hit a daily quota error.

MCP usage counts against the same daily generation quota as the web app. Free is 3 generations / day; Plus is 25; Premium is 100. See /pricing for the current numbers, or upgrade from /settings.

A specific format (e.g. audio) is rejected with an "unavailable" message.

Format gating mirrors the web app. Audio requires Plus or higher; the full 5-format kit requires Plus. Upgrade from /pricing or call `generate_kit` with a subset of formats your tier supports.

The consumer Gemini app's Extensions list has no "Add custom" or "MCP server" option.

Third-party MCP support in the consumer Gemini app's Extensions surface is still rolling out behind a feature flag — if your app only shows Google's first-party extensions (Gmail, Drive, Maps, etc.), your account doesn't have it yet, and nothing on the HippoKit side can speed it up. Use the Gemini CLI path above instead; it's the supported route today.

Gemini answers from its own knowledge instead of calling HippoKit.

Gemini prefers its own context for short prompts. Name HippoKit explicitly: "Use the HippoKit extension to generate flashcards on photosynthesis." Once Gemini has called HippoKit once in a conversation, it usually keeps calling it for follow-ups.

FAQ

Is HippoKit's MCP server free to use?

Yes — MCP usage is included in every HippoKit plan, including Free. There is no separate "API" tier. MCP calls count against the same daily generation quota you see in the web app, so a flashcard set generated through Claude Desktop costs you the same as one generated on hippokit.ai.

What can HippoKit do once connected?

The MCP server exposes nine tools: generate_kit, list_my_kits, get_kit, search_public_kits, claim_preview_kit, get_due_cards, review_card, start_quiz, and answer_quiz_question. Hosts can use these to generate new study content, list your existing library, look up specific kits, browse the public gallery, and run review sessions over your flashcard decks and quizzes.

Can I revoke access?

Yes — revoke any time from https://hippokit.ai/settings/mcp. Revocation is immediate; the host's next request gets a 401 and you can re-issue a fresh token whenever you want.

Does HippoKit see my host conversations?

No. The host only sends HippoKit the structured arguments for the tool calls it makes (e.g. "topic: photosynthesis, formats: flashcards"). The rest of your conversation stays inside the host. We never receive transcripts of your prompts to Claude / ChatGPT / Gemini / Cursor.

Does HippoKit work on Gemini Workspace?

Yes, with the same Extensions UI as consumer Gemini. Workspace admins may need to allow third-party extensions in the admin console; once allowed, individual users authenticate with their own HippoKit PATs.

Can Gemini export a HippoKit kit into Google Slides or Docs?

Indirectly. HippoKit's slide and ebook outputs are downloadable as PPTX and PDF; Gemini can take those download URLs and use its native Drive integration to save them into a Workspace drive. We're tracking a direct Slides/Docs handoff as a future improvement.

Connecting a different host?

HippoKit's MCP server works the same way across every host. Pick yours from the apex docs page.

All MCP hosts

Last reviewed . Found something out of date? Email hello@hippokit.ai and we'll fix it.