Today we're releasing stigmem v1.0 — a stable, open-source specification and reference implementation for a federated knowledge fabric for AI agents.

If you've ever wanted your AI agents to share what they know — across tools, platforms, and organizations — without a central database or a proprietary protocol, stigmem is built for that.

The problem​

Multi-agent systems accumulate knowledge in isolated silos. One agent knows a user prefers dark mode. Another inferred which projects are high priority. A third discovered a bug in the payment flow. None of them can see what the others know, because there's no shared place to put typed, provenance-tagged facts that travel across tool boundaries.

Existing approaches patch around this: you copy facts into prompts, maintain per-agent memory stores, or route everything through a central coordinator. These work up to a point, but they don't scale across organizations, they discard provenance, and they require trust in a single broker.

Stigmem takes a different path. Agents write facts into a shared substrate. The facts replicate across peer nodes via signed, scope-limited federation. No central coordinator. No broker. The knowledge environment itself carries the coordination signal — the same principle that makes ant colonies work, without any ant knowing the global plan.

What stigmem is​

A fact in stigmem is an immutable seven-tuple:

(entity, relation, value, source, timestamp, confidence, scope)

• entity — the URI of the thing being described (user:alice, project:payments, stigmem://company.example/task/t-42)
• relation — the predicate (memory:prefers, status:blocked, infers:next_action)
• value — typed payload: string, number, boolean, JSON object
• source — who asserted this fact (an agent ID, a tool name, a user session)
• timestamp — a Hybrid Logical Clock value that stays monotonic across distributed nodes
• confidence — 0.0–1.0 float; decays over time if not re-asserted
• scope — access boundary (public, company, team, private)

Facts are immutable. If you need to update a fact, you assert a newer one — the old one stays in history for audit. Contradictions between nodes are surfaced as first-class conflict records, not silently overwritten.

The v1.0 milestone​

The v1.0 spec (all 18 sections stable) includes:

• Core fact shape and provenance (§2–3) — the seven-tuple, valid_until expiry, and contradiction detection
• HTTP wire format (§5) — assert, query, retract, single-fact GET, and lint endpoints
• Auth (§3.5) — API keys with per-scope restrictions
• Federation (§6) — PeerDeclaration handshake over Ed25519, pull replication with configurable intervals, scope enforcement across nodes, and backpressure for N-node topologies
• MCP adapter (§12) — ships stigmem as an MCP server so any MCP-compatible agent runtime can read and write facts without knowing the HTTP wire format
• Decay sweep (§15) — configurable TTL and confidence-decay policies via POST /v1/decay/sweep
• Synthesis (§16) — POST /v1/synthesis aggregates recent facts into a structured summary; also exposed as the synthesize_scope MCP tool
• Memory Garden (§17) and Source Attestation (§18) — promoted from the pre-reset spec draft to stable

The reference node is a FastAPI + SQLite implementation with 74 tests, including automated failure-mode tests for split-brain, malicious peers, partial failures, and replay attacks (§11).

Federation in practice​

Two nodes federating takes under two minutes with Docker:

git clone https://github.com/eidetic-labs/stigmem && cd stigmem
docker compose up --build -d

# Register peers (both directions)
docker exec stigmem-node-a-1 \
  stigmem federation register-peer \
    --local-url http://node-a:8765 --remote-url http://node-b:8765 --scopes company,public

docker exec stigmem-node-b-1 \
  stigmem federation register-peer \
    --local-url http://node-b:8765 --remote-url http://node-a:8765 --scopes company,public

# Assert a fact on node-a
curl -s -X POST http://localhost:8765/v1/facts \
  -H 'Content-Type: application/json' \
  -d '{
    "entity": "user:alice",
    "relation": "memory:prefers",
    "value": {"type": "string", "v": "dark mode"},
    "source": "agent:settings",
    "confidence": 1.0,
    "scope": "company"
  }' | jq .

# After ~30 s, verify replication on node-b
curl -s 'http://localhost:8766/v1/facts?entity=user:alice&scope=company' | jq .facts

The two nodes discover each other via the /.well-known/stigmem metadata endpoint, exchange Ed25519-signed PeerDeclarations, and begin pull replication on the interval you configure (STIGMEM_FEDERATION_PULL_INTERVAL_S, default 30 s).

Scope enforcement is strict: a fact written to the company scope on node-a only replicates to peers that declared company in their handshake. private scope facts never leave the node that created them.

MCP integration​

Stigmem ships an MCP adapter, so any agent runtime that speaks MCP can interact with a stigmem node without calling the HTTP API directly:

{
  "mcpServers": {
    "stigmem": {
      "command": "npx",
      "args": ["-y", "@stigmem/mcp-server"],
      "env": { "STIGMEM_NODE_URL": "http://localhost:8765" }
    }
  }
}

Once connected, agents get tools: assert_fact, query_facts, retract_fact, synthesize_scope, and lint_scope. The synthesis tool is particularly useful — it aggregates recent facts in a scope into a structured narrative that can be injected directly into an agent's context window.

What stigmem is not​

Stigmem does not replace:

• Agent runtimes (Claude Code, OpenClaw) — stigmem is the shared substrate those runtimes reason over, not a runtime itself
• Orchestration platforms (Paperclip) — the Paperclip adapter emits issue lifecycle events as stigmem facts; they layer, not compete
• Tool protocols (MCP) — MCP is the transport; the stigmem MCP adapter rides on top

It fills the gap none of them fill: typed, provenance-traceable, expiry-aware, federated shared knowledge.

Get started​

Self-hosted: docs.stigmem.dev/docs/getting-started/quickstart

Repo: github.com/eidetic-labs/stigmem — Apache 2.0

Spec: spec/stigmem-spec-v1.0.md — all 18 sections stable

Free-tier hosted node: coming soon — join the list

We'd love to hear what you're building. Open a discussion on GitHub, or drop a comment below.