Gemini Spark

Long-term memory for Gemini Spark, Google's always-on agentic assistant, via Hindsight's MCP server.

Hindsight Cloud (recommended)

Sign up free — get an API key instantly, no infrastructure to run. The setup below works with both Cloud and self-hosted Hindsight.

How It Works

Spark runs on Google's cloud infrastructure. Unlike OpenClaw or Claude Code, there is no plugin host where Hindsight code runs alongside Spark's agent loop. The only third-party extension surface is MCP:

Capability	Spark support
Hook-based auto-recall (prepend context to the prompt)	Not available — Spark's prompt assembly is private. The agent calls recall when its planner judges it useful.
Hook-based auto-retain (save transcripts on turn end)	Not available — third parties don't see Spark's transcripts. The agent calls retain when it learns something worth keeping.
MCP tools (recall, retain, etc.)	Yes — Spark calls Hindsight's MCP tools via its built-in MCP client.

Architecture

With Hindsight Cloud (recommended)

Gemini Spark (Google Cloud)
        |
        | HTTPS + MCP (Streamable HTTP)
        v
Hindsight Cloud (api.hindsight.vectorize.io)

With self-hosted Hindsight

Gemini Spark (Google Cloud)
        |
        | HTTPS + OAuth 2.1 (Spark's MCP client)
        v
Cloudflare Worker — cloudflare-oauth-proxy
   - OAuth authorization server
   - Auth bridging to Hindsight API token
        |
        | HTTPS + Cloudflare Tunnel
        v
Self-hosted Hindsight + hindsight-embed (MCP server)

Setup

Option 1: Hindsight Cloud (recommended)

1. Sign up at vectorize.io/hindsight and create a memory bank
2. Copy your API key from the dashboard
3. Register Hindsight in Spark's MCP config (see below)

Option 2: Self-hosted

1. Deploy a Hindsight instance and run the hindsight-embed MCP server pointed at it, exposed on a public HTTPS endpoint
2. Deploy the cloudflare-oauth-proxy — Spark only speaks OAuth 2.1 to MCP servers

Register Hindsight in Spark

Spark (via Antigravity 2.0) reads MCP servers from one of two places:

• Hosted agent / Spark cloud: an antigravity.yaml manifest — see manifest.example.yaml
• Antigravity desktop / IDE: ~/.gemini/antigravity/mcp_config.json — see mcp_config.example.json

Replace the placeholder URL with your Hindsight Cloud endpoint or OAuth proxy URL.

Verifying Setup

Prompt Spark with something that should trigger the memory tools:

• "What were my open API decisions from last week?" → recall
• "Remember that I prefer TypeScript strict mode for new projects." → retain

Example Configs

Both live in the integration directory:

• manifest.example.yaml — Antigravity 2.0 agent manifest snippet
• mcp_config.example.json — Desktop/IDE MCP config for local development