One answers for you.
One hands your agent the evidence.
GBrain, from Garry Tan, is an MIT-licensed memory server for agents, also sold hosted as gbrain.io. Brain is shared memory for teams of agents and people. Both give every MCP client the same memory. They differ on who writes the answer. GBrain details come from its repo and site, reviewed in Aug and Oct 2026.
Where GBrain is ahead
| Capability | GBrain | Brain |
|---|---|---|
| Synthesised answers | think writes a cited answer and notes what the brain doesn't know yet. | Returns cited evidence plus a coverage note (no match, stale, thin entity). Your agent writes the answer. |
| Connectors | Gmail, Calendar, Contacts, voice calls and meeting webhooks feed it directly. | Agents, the API, the web UI and Obsidian write to it. |
| Code intelligence | Callers, callees, definitions, references and blast radius over indexed code. | None. |
| Open source and self-hosting | MIT. Runs on a laptop, and can run fully on local models (Ollama, llama.cpp). | Hosted. On-premise is not generally available yet. |
| Published evals | LongMemEval-S and its own BrainBench, with reproduction commands. | Not published. |
Both do
| Capability | How |
|---|---|
| Hybrid retrieval | Keyword and semantic results fused (RRF), then a cross-encoder rerank. |
| Entity graph | Typed links between people, companies and topics. |
| Corrections | A replaced fact is superseded, not silently overwritten. |
| Near-duplicate checks | Run when knowledge is written. |
| Secret scanning | Credentials are caught at ingest. |
| Skills | Stored beside the knowledge, shared across agents. |
| Shared access | GBrain grants by source and operation; Brain grants by vault. |
Only in Brain
| Capability | Brain | GBrain |
|---|---|---|
| Agent-to-agent handoffs | Agents send each other tasks through a durable inbox. | None. |
| Lineage and trust | Every fact traces to its source documents, with a trust tier and origin. Runbooks are marked draft or ratified. | Provenance and a source-tier ranking boost; no ratification step. |
| Work continuity | Sessions, todos and reminders live next to the memory. | Memory, skills and jobs; no todos or reminders. |
| Tool surface | About 20 MCP tools, so schemas cost little context. | 151 tools, with a ~40-tool starter surface for clients that cap tools. |
Different by design
Who writes the answer
GBrain puts an LLM after retrieval to compose the answer. Brain keeps LLMs out of retrieval: results are fast, deterministic evidence, and the agent holding the task context does the reasoning.
When curation runs
GBrain curates in a nightly cycle of background jobs. Brain curates when knowledge is written, and records each decision with its provenance.
Where GBrain fits
One person or company that wants a brain answering for them, fed from email, calendar and calls. It's MIT-licensed and free to self-host.
Where Brain fits
Several agents and people working from the same memory: shared vaults, handoffs between agents, and facts you can trace back to their source before you act on them.
Benchmarks. GBrain reports LongMemEval-S recall_all@5 of 95.53% (93.40% with rerank off), retrieval only, measured 6 Sep 2026 in its docs. Brain hasn't published scores under a third-party harness, so we don't put the two side by side.
Method. GBrain: repo garrytan/gbrain reviewed 7 Aug 2026, re-checked at commit f3f9dbd on 20 Oct 2026; gbrain.io read 20 Oct 2026. Brain: checked against its source on 20 Oct 2026. Both projects move fast; check the current docs.