brainctl 2.4.1

Context engineering for AI agents — persistent memory, knowledge graph, affect tracking, and MCP server. Single SQLite file, zero LLM cost.

brainctl

Forgetful agents, fixed by a SQLite file.

One brain.db gives your agent durable memory across sessions — facts learned, decisions made, entities tracked, and state handed off. No server. No API keys. No LLM calls required.

from agentmemory import Brain

brain = Brain(agent_id="my-agent")
ctx = brain.orient(project="api-v2")           # session start: handoff + events + triggers + memories
brain.remember("rate-limit: 100/15s", category="integration")
brain.decide("use Retry-After for backoff", "server controls timing", project="api-v2")
brain.wrap_up("auth module complete", project="api-v2")  # session end: logs + handoff for next run

Install

pip install brainctl

Requires Python 3.11+. SQLite is built-in. No other mandatory dependencies.

pip install brainctl[mcp]     # MCP server — 201 tools for Claude Desktop, Cursor, VS Code
pip install brainctl[vec]     # vector similarity search (sqlite-vec + Ollama)
pip install brainctl[signing] # Ed25519-signed memory exports + optional Solana on-chain pinning
pip install brainctl[all]     # everything

5-line example

from agentmemory import Brain

brain = Brain(agent_id="research-bot")
brain.remember("OpenAI rate-limits at 500k TPM on tier 3", category="integration")
results = brain.search("rate limit")          # FTS5 full-text, stemming, ranked
brain.entity("OpenAI", "service", observations=["500k TPM tier 3", "REST API"])
brain.relate("OpenAI", "provides", "GPT-4o")

Feature checklist

Memory types

• convention, decision, environment, identity, integration, lesson, preference, project, user
• Category controls natural half-life: identity decays over ~1 year; integration details over ~1 month
• Hard cap: 10,000 memories per agent. Emergency compression retires lowest-confidence entries.

Retrieval modes

• FTS5 full-text search with stemming (default, zero dependencies)
• Vector similarity via sqlite-vec + Ollama nomic-embed-text (brainctl[vec])
• Hybrid: Reciprocal Rank Fusion over FTS5 + vector results
• Context profiles: named search presets scoped to task type (--profile ops, --profile research, etc.)
• --benchmark preset: flattens recency/salience for synthetic evaluation runs

Reranker chain

• Intent classifier (regex, 10 labels → 6 profiles) routes queries at cmd_search
• Post-FTS reranking by recency, salience, Q-value utility, and Bayesian recall confidence
• Cold-start: auto-detects available reranker backends (cross-encoder > sentence-transformers > fallback)
• Retrieval regression-gated in CI: >2% drop on P@1/P@5/MRR/nDCG@5 fails the build

Knowledge graph

• Typed entity nodes: agent, concept, document, event, location, organization, person, project, service, tool
• Auto entity linking: memories mentioning a known entity create the edge automatically
• Compiled truth synthesis per entity (brainctl entity compile <name>)
• 3-level enrichment tier; canonical alias dedup (brainctl entity alias add)
• Spreading-activation recall across the graph (brain.think(query))

Belief revision (AGM)

• Belief set per agent with confidence weights
• Conflict detection and resolution via brainctl belief conflicts and brainctl belief merge
• Collapse mechanics: decoherent beliefs quarantined, recovery candidates surfaced
• PII recency gate (Proactive Interference Index) on supersedes operations

Signed exports

• brainctl export --sign produces a portable Ed25519-signed JSON bundle
• brainctl verify <bundle.json> checks the signature offline — no brainctl required for verification
• Optional: --pin-onchain writes the SHA-256 hash as a Solana memo transaction (~$0.001 per pin)
• Managed wallet: brainctl wallet new creates a local keypair at ~/.brainctl/wallet.json for users without an existing Solana setup
• Memories never leave the machine; only the hash goes on-chain (opt-in)

Plugins (16 first-party)

Agent frameworks:

Plugin	Target
plugins/claude-code/	Claude Code
plugins/codex/	OpenAI Codex CLI
plugins/cursor/	Cursor
plugins/gemini-cli/	Gemini CLI
plugins/eliza/	Eliza (TypeScript)
plugins/hermes/	Hermes Agent
plugins/openclaw/	OpenClaw
plugins/rig/	Rig
plugins/virtuals-game/	Virtuals Game
plugins/zerebro/	Zerebro

Trading bots:

Plugin	Target
plugins/freqtrade/	Freqtrade
plugins/jesse/	Jesse
plugins/hummingbird/	Hummingbird
plugins/nautilustrader/	NautilusTrader
plugins/octobot/	OctoBot
plugins/coinbase-agentkit/	Coinbase AgentKit

MCP server (201 tools)

{
  "mcpServers": {
    "brainctl": {
      "command": "brainctl-mcp"
    }
  }
}

Add to ~/.claude/claude_desktop_config.json, ~/.cursor/mcp.json, or equivalent. Full tool list and a decision tree: MCP_SERVER.md.

CLI reference

brainctl memory add "content" -c convention   # store a memory
brainctl search "query"                       # FTS5 search
brainctl vsearch "semantic query"             # vector search (requires [vec])
brainctl entity create "Alice" -t person      # create entity
brainctl entity relate Alice works_at Acme    # link entities
brainctl event add "deployed v3" -t result    # log an event
brainctl decide "title" -r "rationale"        # record a decision
brainctl export --sign -o bundle.json         # signed export
brainctl verify bundle.json                   # verify a bundle
brainctl wallet new                           # create managed signing wallet
brainctl stats                                # DB overview
brainctl doctor                               # health check
brainctl lint                                 # quality issues
brainctl gaps scan                            # coverage + orphan + broken-edge scans
brainctl consolidate cycle                    # full consolidation pass

Python API (22 methods)

Method	What it does
orient(project)	One-call session start: handoff + events + triggers + memories
wrap_up(summary)	One-call session end: logs event + creates handoff
remember(content, category)	Store a durable fact through the W(m) write gate
search(query)	FTS5 full-text search with stemming
vsearch(query)	Vector similarity search (optional)
think(query)	Spreading-activation recall across the knowledge graph
forget(memory_id)	Soft-delete a memory
entity(name, type)	Create or retrieve an entity
relate(from, rel, to)	Link two entities
log(summary, type)	Log a timestamped event
decide(title, rationale)	Record a decision with reasoning
trigger(condition, keywords, action)	Set a prospective reminder
check_triggers(query)	Match triggers against text
handoff(goal, state, loops, next)	Save session state explicitly
resume()	Fetch and consume latest handoff
doctor()	Diagnostic health check
consolidate()	Promote high-importance memories
tier_stats()	Write-tier distribution
stats()	Database overview
affect(text)	Classify emotional state
affect_log(text)	Classify and store emotional state
close()	Close the shared SQLite connection

Memory lifecycle

• Write gate (W(m)): surprise scoring rejects redundant writes. Bypass with force=True.
• Three-tier routing: high-value memories get full indexing; low-value get lightweight storage.
• Duplicate suppression: near-duplicates reinforce existing memories instead of creating new rows.
• Half-life decay: unused memories fade at a rate set by category. Recalled memories are reinforced.
• Consolidation: Hebbian learning, temporal promotion, compression — runs on a cron schedule.

Retrieval benchmarks

Tested with default settings, no tuning for benchmark data. Backend: Brain.search.

LongMemEval (289 questions, 4 categories):

metric	overall	single-session-assistant	single-session-user	multi-session
hit@1	0.882	1.000	0.900	0.910
hit@5	0.976	1.000	1.000	0.985
MRR	0.924	1.000	0.935	0.944

LOCOMO (1,982 questions, 5 categories, 10 conversations):

metric	overall	adversarial	temporal	open-domain	single-hop	multi-hop
hit@1	0.341	0.377	0.405	0.373	0.167	0.174
hit@5	0.572	0.603	0.648	0.602	0.429	0.315
MRR	0.445	0.479	0.510	0.479	0.282	0.232

LOCOMO single-hop and multi-hop hit@1 are weak (0.167 / 0.174). Root cause: recency and salience rerankers bias toward recent memories; LOCOMO uses uniform synthetic timestamps with gold evidence concentrated in early sessions, so the rerankers fight FTS ranking. A --benchmark preset that flattens recency/salience is available for evaluation runs. See tests/bench/ for the full harness.

Upgrading

cp $BRAIN_DB $BRAIN_DB.pre-upgrade
brainctl doctor      # diagnose migration state
brainctl migrate     # apply pending migrations

For databases predating the migration tracker, see the full recovery workflow in the README's Upgrading section (below the install block in the full docs).

Multi-agent

researcher = Brain(agent_id="researcher")
writer     = Brain(agent_id="writer")

researcher.remember("API uses OAuth 2.0 PKCE", category="integration")
writer.search("OAuth")   # finds researcher's memory — same brain.db, shared graph

Every operation accepts agent_id for attribution. Agents share one brain.db. The knowledge graph connects insights across agents automatically.

Documentation

Doc	What it covers
docs/QUICKSTART.md	60-second onboarding — install, remember, search, sign
docs/COMPARISON.md	Feature matrix vs Mem0, Letta, Zep, Cognee, OpenAI Memory
docs/AGENT_ONBOARDING.md	Step-by-step agent integration guide
docs/AGENT_INSTRUCTIONS.md	Copy-paste blocks for MCP, CLI, Python agents
docs/SIGNED_EXPORTS.md	Bundle format, threat model, verify-without-brainctl recipe
MCP_SERVER.md	201 tools with decision tree
ARCHITECTURE.md	Technical deep-dive

License

MIT