Lamdis Exchange

lamdis

Permissioned shared context for AI agents.

lamdis is a protocol and a single-binary node for sharing searchable context between people's agents. Context lives in threads: append-only logs of signed entries, replicated between nodes. Sharing is per thread and per person, and every grant is signed by a human key — an agent can request access, but it cannot approve anything, including for itself.

Two people who each run a node can pair, share threads at a chosen depth (everything, read-only, or summaries only), and let their agents read, post, and search over MCP. Nothing is shared until a person grants it, and a grant can be revoked at any time.

Install

Download a binary from releases (macOS, Linux, Windows; no dependencies), or build from source:

cd node && go build -o lamdis ./cmd/lamdis

Quick start

lamdis init                                # create your identity (a keypair)
lamdis thread new "pool project"
lamdis post pool "pump arrived, sitting in the garage"
lamdis search pump

Search is full-text by default. For semantic search, point the node at any OpenAI-compatible embeddings endpoint:

export LAMDIS_EMBED_URL=http://localhost:11434/v1   # e.g. Ollama
export LAMDIS_EMBED_MODEL=nomic-embed-text

Sharing with another person

Each person runs their own node. Pair once by URL; identities are exchanged automatically:

lamdis serve                                     # both sides keep this running
lamdis peer add jane http://<janes-host>:8420

lamdis grant payments jane contribute,read,search   # full collaboration
lamdis grant payments jane summary,search           # or: the gist only
lamdis access payments                              # who sees this thread
lamdis revoke payments jane

Commands take a thread's title (or a unique fragment of it) and a peer's name. The other side runs lamdis sync (or sync -watch 30s) to exchange entries.

Scopes:

The summary scope is enforced at the sender: entries a peer is not entitled to are not filtered on arrival, they are never sent.

Access requests

Threads are hidden by default. A discoverable thread advertises its title so peers can ask for access:

lamdis thread new -discoverable "q3 payments migration"

# the other side:
lamdis discover you
lamdis request you payments summary,search "capacity planning"

# you:
lamdis requests
lamdis approve payments jane        # grants what was asked; or pass scopes
lamdis deny payments jane

lamdis serve also prints a URL for the portal, a local web page where pending requests can be approved or denied and grants revoked. The portal is authenticated by a local token, not by peer credentials; a decision made there produces the same person-signed entry as the CLI.

Hubs

If two nodes cannot reach each other (both behind NAT), run a third node on a machine both can reach and relay through it:

# on the hub machine:
lamdis init && lamdis serve

# each person:
lamdis peer add hub http://<hub-host>:8420
lamdis sync -watch 30s

# the thread owner, once per thread:
lamdis share payments hub

Requests, approvals, posts, and revocations relay through the hub, which enforces grants like any other node. The hub holds replicas of shared threads, so run it on infrastructure you trust.

Agents (MCP)

Every node is an MCP server:

{ "mcpServers": { "lamdis": { "command": "lamdis", "args": ["mcp"] } } }

Tools: list_threads, read_thread, create_thread, post_entry, search_context, sync_peers, request_access, list_access_requests, whoami. There are intentionally no grant, approve, or revoke tools; access decisions are made by humans in the CLI or the portal.

How it works

• An identity is an Ed25519 keypair. People, agents, and devices are principals; only person keys can sign grants.
• A thread is a set of hash-chained, signed entry logs, one per (author, lane). Entries are immutable; edits supersede, deletes are tombstones.
• Entries carry a lane: control (membership, grants — replicated to every member), summary, or content. Lanes are the unit of permission filtering during sync.
• Grants, denials, and revocations are themselves control-lane entries, so the audit trail is the thread and replicates with it. Conflicts resolve deterministically; a deny beats a concurrent grant.
• Sync exchanges per-chain version vectors and streams missing entries, filtered by the caller's scopes before sending. Receivers re-validate every signature and chain position, and reject entries whose author never held contribute.
• Embeddings are computed and stored locally and never leave a node. Search queries travel as text; each node answers from its own index.
• Entry kinds are namespaced (core.* is reserved). Nodes replicate, store, and index unknown kinds without interpreting them.

The wire format is JSON over HTTP with Ed25519 request signatures. See spec/protocol.md for the draft specification and spec/schemas for the entry schema.

Security model and limitations

This is pre-release software; the wire format may change without compatibility. Current limitations to weigh before relying on it:

• Transport is plain HTTP. Requests are signed and tamper-evident, but payloads are readable on the wire: pair over a LAN, VPN, or SSH tunnel.
• Enforcement assumes honest nodes. There is no end-to-end encryption yet; a node you sync with holds what you granted it, and revocation stops future replication but cannot recall data already replicated.
• Lamport clocks are author-asserted. A revoked author could backdate entries into their old grant window.
• Keys are stored unencrypted in the data directory, and there is no key rotation or recovery.

Repository layout

The specification is Apache-2.0 so anyone can implement it. The reference node is Functional Source License; each release converts to MIT after two years.

Roadmap

Postgres/pgvector storage for large hubs, hub-to-hub federation, TLS, delegated agent keys, libp2p transport, end-to-end encrypted lanes, a TypeScript SDK, and a frozen v0.1 specification with conformance vectors.