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Class: Brain

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:409

Unified cross-platform connection manager for a single agent's persistent brain.

Uses the StorageAdapter interface from @framers/sql-storage-adapter to support multiple backends (better-sqlite3, sql.js, IndexedDB, Postgres, etc.) transparently. All methods are async.

Usage:

const brain = await Brain.open('/path/to/agent/brain.sqlite');

// Async query API for subsystems
const row = await brain.get<{ value: string }>('SELECT value FROM brain_meta WHERE key = ?', ['schema_version']);

// Meta helpers
await brain.setMeta('last_sync', Date.now().toString());
const ver = await brain.getMeta('schema_version'); // '1'

await brain.close();

Subsystems (KnowledgeGraph, MemoryGraph, ConsolidationLoop, etc.) receive the Brain instance and call its async proxy methods (run, get, all, exec, transaction) for all database operations.

Accessors​

adapter​

Get Signature​

get adapter(): StorageAdapter

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:664

Expose the raw storage adapter for advanced usage.

Primarily used by SqliteExporter (VACUUM INTO) and SqliteImporter (which needs direct adapter access for the target brain).

Returns​

StorageAdapter

brainId​

Get Signature​

get brainId(): string

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:456

Brain identifier scoping every query through this Brain instance. Subsystems (KnowledgeGraph, MemoryGraph, ConsolidationLoop) read this to inject brain_id into their own SQL.

Returns​

string

features​

Get Signature​

get features(): StorageFeatures

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:673

Platform-aware feature bundle (dialect, FTS, BLOB codec, exporter). Consumers use this to generate cross-platform SQL instead of hardcoding SQLite-specific syntax.

Returns​

StorageFeatures

Methods​

all()​

all<T>(sql, params?): Promise<T[]>

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:632

Retrieve all rows matching the statement.

Type Parameters​

T​

T = unknown

Parameters​

sql​

string

SQL SELECT statement.

params?​

StorageParameters

Parameter array.

Returns​

Promise<T[]>

Array of matching rows (empty array if none).

checkEmbeddingCompat()​

checkEmbeddingCompat(dimensions): Promise<boolean>

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:812

Check whether a given embedding dimension is compatible with this brain.

On first call (no stored embedding_dimensions), returns true and stores the provided dimension for future compatibility checks.

Subsequent calls compare dimensions against the stored value. Mismatches indicate that a different embedding model was used to encode memories — mixing dimensions would corrupt vector similarity searches.

Parameters​

dimensions​

number

The embedding vector length to check (e.g. 1536 for OpenAI ada-002).

Returns​

Promise<boolean>

true if compatible (or no prior value), false on mismatch.

close()​

close(): Promise<void>

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:1036

Close the database connection.

Must be called when the agent shuts down to flush the WAL and release the file lock. Failing to close may leave the database in WAL mode with an unconsumed WAL file.

Returns​

Promise<void>

exec()​

exec(sql): Promise<void>

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:641

Execute a script containing multiple SQL statements.

Parameters​

sql​

string

SQL script (semicolon-delimited statements).

Returns​

Promise<void>

exportToSqlite()​

exportToSqlite(targetPath): Promise<{ bytesWritten: number; }>

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:844

Materialize this brain to a portable SQLite file at targetPath.

Source can be any backend (SQLite, Postgres, Capacitor, etc.); output is always a fresh SQLite file. Used by .wildsoul-style export and other portability flows.

Refuses to overwrite an existing file at targetPath so callers do not silently lose data.

Forking semantics: rows are emitted with the source brainId. Importing the resulting file under a different brainId produces a fork.

Parameters​

targetPath​

string

Destination file path. File must not exist.

Returns​

Promise<{ bytesWritten: number; }>

Bytes written to the destination file.

get()​

get<T>(sql, params?): Promise<T | null>

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:621

Retrieve a single row (or null if none found).

Type Parameters​

T​

T = unknown

Parameters​

sql​

string

SQL SELECT statement.

params?​

StorageParameters

Parameter array.

Returns​

Promise<T | null>

First matching row or null.

getMeta()​

getMeta(key): Promise<string | undefined>

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:769

Read a value from the brain_meta key-value store.

Parameters​

key​

string

The metadata key to look up.

Returns​

Promise<string | undefined>

The stored string value, or undefined if the key does not exist.

importFromSqlite()​

importFromSqlite(sourcePath, opts?): Promise<{ tablesImported: Record<string, number>; }>

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:901

Load a portable SQLite file into this Brain's adapter.

Forking semantics: rows from the source file are written under the RECEIVING brain's brainId, not the brainId stored in the source file. This means importing an alice snapshot into a Brain opened with brainId: 'alice-fork' produces a fork with no shared identity.

CAVEAT: importing from a pre-0.3.0 SQLite file MUTATES the source file. Opening the source via Brain.openSqlite runs the v1 to v2 migration in place. To preserve the source unchanged, copy the file to a temp path before calling this method.

Parameters​

sourcePath​

string

Source SQLite file path (typically produced by Brain.exportToSqlite).

opts?​
strategy?​

"merge" | "replace"

'merge' (default) upserts on PK collision; 'replace' wipes all rows for the receiving brainId first.

Returns​

Promise<{ tablesImported: Record<string, number>; }>

Counts of rows imported per table.

run()​

run(sql, params?): Promise<StorageRunResult>

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:610

Execute a mutation statement (INSERT, UPDATE, DELETE).

Parameters​

sql​

string

SQL statement with ? positional placeholders.

params?​

StorageParameters

Parameter array matching the placeholders.

Returns​

Promise<StorageRunResult>

Metadata about affected rows.

setMeta()​

setMeta(key, value): Promise<void>

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:787

Upsert a value into the brain_meta key-value store.

Uses INSERT OR REPLACE semantics — creates the row if absent, or overwrites if present.

Parameters​

key​

string

The metadata key.

value​

string

The string value to store.

Returns​

Promise<void>

transaction()​

transaction<T>(fn): Promise<T>

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:654

Execute a callback within a database transaction.

The transaction is automatically committed on success or rolled back on error.

Type Parameters​

T​

T

Parameters​

fn​

(trx) => Promise<T>

Async callback receiving a transactional adapter.

Returns​

Promise<T>

Result of the callback.

openPostgres()​

static openPostgres(connectionString, opts): Promise<Brain>

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:511

Open a Brain backed by PostgreSQL. Requires the pg npm package and a reachable Postgres instance.

Parameters​

connectionString​

string

Standard Postgres connection URL.

opts​
brainId​

string

REQUIRED. Used to scope every query so multiple brains can share one Postgres database without leaking rows.

poolSize?​

number

pg connection pool size. Defaults to 10.

Returns​

Promise<Brain>

openSqlite()​

static openSqlite(path, opts?): Promise<Brain>

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:486

Open a Brain backed by SQLite. Tries adapters in order: better-sqlite3 (Node native) -> sql.js (WASM) -> indexeddb (browser).

Parameters​

path​

string

File path. Use :memory: for in-process testing.

opts?​
brainId?​

string

Optional explicit brainId; defaults to file basename (or 'default' for :memory:).

priority?​

("better-sqlite3" | "sqljs" | "indexeddb")[]

Override the default adapter priority.

Returns​

Promise<Brain>

A fully initialised Brain instance with the v2 schema.

openWithAdapter()​

static openWithAdapter(adapter, opts?): Promise<Brain>

Defined in: packages/agentos/src/memory/retrieval/store/Brain.ts:557

Open a Brain with a pre-resolved StorageAdapter. Use when sharing an adapter across subsystems (e.g., wilds-ai foundation pool + brain) or when the consumer needs full control over adapter resolution.

CONCURRENCY CAVEAT (Postgres adapters): the underlying PostgresAdapter tracks transactionalClient as instance-shared mutable state. Two concurrent Brain.transaction(...) calls on the same shared adapter (or any subsystem call that internally opens a transaction) will overwrite each other's connection assignment, which corrupts both transactions silently. If the consumer dispatches concurrent writes through subsystems sharing one adapter, either:

  1. construct a fresh PostgresAdapter per logical actor, OR
  2. serialize transactions at the consumer layer until the adapter gets AsyncLocalStorage-tracked transactional clients. Non-transactional concurrent reads/writes against a shared adapter are safe (the pool handles those correctly).

Parameters​

adapter​

StorageAdapter

Pre-built StorageAdapter instance.

opts?​
brainId?​

string

Required for postgres-kind adapters; optional for sqlite-kind adapters (defaults to 'default').

Returns​

Promise<Brain>