---
name: agentmemory-architecture
description: How agentmemory is built, the single in-process engine it runs on, its storage model, ports, and the viewer. Use when reasoning about how memory is stored or retrieved end to end, when extending the system, or when answering how agentmemory works under the hood.
user-invocable: false
---

agentmemory is a memory server for coding agents. It runs locally, captures observations, indexes them for hybrid retrieval, and serves them back over REST and MCP. It is a single Node process with no external services.

## One in-process Engine

Starting agentmemory is the whole deployment: one process opens a SQLite file, registers every operation as a named function (`mem::*`) plus HTTP triggers (`api::*`), and dispatches calls by id without leaving the process. There is no second daemon to install or supervise, and no separate plugin system; new capability is a new function plus a trigger.

## Retrieval model

Recall is hybrid: BM25 keyword search plus vector similarity plus graph expansion over linked concepts. The default install needs no API key because embeddings run on-device and BM25 needs none. An LLM provider only adds richer summaries and auto-injection, both opt-in.

## Storage and lifecycle

Everything persists to one SQLite file (`<data-dir>/agentmemory.sqlite`, overridable with `AGENTMEMORY_SQLITE_PATH`): key-value state in a `kv` table and embeddings in a `vectors` table. Memories carry content, concepts, files, importance, and timestamps, grouped into sessions and optionally linked to commits. A lifecycle of capture, compress, consolidate, and forget keeps the store useful over time rather than letting it grow unbounded.

## Ports

REST is the anchor at 3111. Streams = N+1 (3112), viewer = N+2 (3113). Three ports, no fourth. `--instance N` shifts the whole block by N*100.

## Viewer

A real-time web viewer at `http://localhost:3113` shows memory building as sessions run. Useful for demos and for confirming capture is working.

## See also

- agentmemory-mcp-tools and agentmemory-rest-api for the surfaces.
- agentmemory-hooks for automatic capture.
- agentmemory-config for ports and feature flags.