rcan 3.4.1

Official Python SDK for the RCAN robot communication protocol

rcan-py

Python SDK for the RCAN protocol. Build robots that communicate securely, audit every action, enforce safety gates locally, and register with the Robot Registry Foundation. Pinned protocol version: see the live compatibility matrix.

Where this fits in the stack

This repo is the Python SDK layer — the library any Python planner, gateway, or driver links against to speak RCAN. Everything below is independent; adopt one, or all seven.

Layer	Piece	What it is
Declaration	ROBOT.md	The file a robot ships at its root. YAML frontmatter + markdown prose. Declares identity, capabilities, safety gates. Spec + Python CLI.
Agent bridge	robot-md-mcp	MCP server that exposes a ROBOT.md to Claude Code, Claude Desktop, Cursor, Zed, Gemini CLI — any MCP-aware agent.
Wire protocol	RCAN	How robots, gateways, and planners talk. Signed envelopes, LoA enforcement, PQC crypto. Think HTTP for robots.
Python SDK ← this	rcan-py	pip install rcan — RCANMessage, RobotURI, ConfidenceGate, HiTLGate, AuditChain, RegistryClient.
TypeScript SDK	rcan-ts	npm install rcan-ts — same API surface for Node + browser.
Registry	Robot Registry Foundation	Permanent RRN identities. Public resolver at /r/<rrn>. Like ICANN for robots.
Reference runtime	OpenCastor	Open-source robot runtime — connects LLM brains to hardware bodies. One implementation of RCAN.

Install

pip install rcan

Optional extras:

pip install rcan[http]    # httpx for registry client
pip install rcan[crypto]  # cryptography for Ed25519 signing
pip install rcan[all]     # everything

Quick Start

from rcan import RobotURI, RCANMessage, ConfidenceGate
from rcan.audit import AuditChain, CommitmentRecord
from rcan.replay import ReplayCache
from rcan.qos import QoSLevel
from rcan.consent import ConsentRequest

# 1. Address a robot
uri = RobotURI.build(manufacturer="acme", model="arm", version="v2", device_id="unit-001")
# rcan://registry.rcan.dev/acme/arm/v2/unit-001

# 2. Gate on AI confidence before acting
gate = ConfidenceGate(threshold=0.8)
confidence = 0.91

if gate.allows(confidence):
    msg = RCANMessage(
        cmd="move_forward",
        target=uri,
        params={"distance_m": 1.0},
        confidence=confidence,
        model_identity="gemini-2.5-flash",
    )

# 3. Replay attack prevention — deduplicate incoming messages
cache = ReplayCache(window_seconds=300)
if cache.is_replay(msg.msg_id):
    raise ValueError("Replay attack detected")
cache.record(msg.msg_id)

# 4. Tamper-evident audit chain — every action sealed and linked
chain = AuditChain(secret="your-hmac-secret")
chain.append(CommitmentRecord(
    action="move_forward",
    robot_uri=str(uri),
    confidence=confidence,
    model_identity="gemini-2.5-flash",
    safety_approved=True,
))
chain.verify_all()  # raises if chain is tampered

# 5. Request human consent before a sensitive action
req = ConsentRequest(
    action="open_gripper",
    robot_uri=str(uri),
    requester="operator-alice",
    scope="control",
)
print(req.to_json())

What's in v0.6.0

Module	Description
rcan.message	Core RCANMessage envelope with all v1.6 fields
rcan.address	RobotURI — parse, build, and validate RCAN robot addresses
rcan.audit	AuditChain + CommitmentRecord — tamper-evident HMAC-chained logs
rcan.gates	ConfidenceGate, HiTLGate — safety gates for AI-driven actions
rcan.replay	ReplayCache — sliding-window replay attack prevention (GAP-03)
rcan.clock	ClockSyncStatus — NTP clock sync verification (GAP-04)
rcan.qos	QoSLevel — FIRE_AND_FORGET / ACKNOWLEDGED / EXACTLY_ONCE (GAP-11)
rcan.consent	Consent wire protocol — request/grant/deny (GAP-05)
rcan.revocation	Robot identity revocation with TTL cache (GAP-02)
rcan.training_consent	Training data consent, GDPR/EU AI Act Annex III §5 (GAP-10)
rcan.delegation	Command delegation chain, max 4 hops, Ed25519-signed (GAP-01)
rcan.offline	Offline operation mode — ESTOP always allowed (GAP-06)
rcan.fault	FaultCode structured fault taxonomy (GAP-20)
rcan.federation	Federated consent — cross-registry trust, DNS discovery (GAP-16)
rcan.transport	Constrained transports — compact CBOR, 32-byte ESTOP minimal, BLE (GAP-17)
rcan.multimodal	Multi-modal payloads — inline/ref media, streaming (GAP-18)
rcan.identity	Level of Assurance — LoA policies, JWT parsing (GAP-14)
rcan.keys	Key rotation with JWKS-compatible KeyStore (GAP-09)
rcan.config_update	CONFIG_UPDATE protocol with safety scope enforcement (GAP-07)
rcan.node	NodeClient — resolve RRNs across federated registry nodes (§17)
rcan.validate	L1/L2/L3 conformance validation for configs, messages, URIs

Protocol 66 Compliance

Protocol 66 is RCAN's safety layer. Key invariants enforced by this SDK:

• ESTOP always delivered — QoSLevel.EXACTLY_ONCE, never blocked by QoS downgrade
• Local safety wins — offline module enforces local limits even without cloud connectivity
• Confidence gates run locally — ConfidenceGate never makes a network call
• Audit chain required — AuditChain.verify_all() before executing any flagged command

from rcan.offline import OfflineMode
from rcan.safety import SafetyInvariant

mode = OfflineMode()
mode.assert_estop_reachable()   # raises if ESTOP path is blocked

CLI

# Validate a robot config (L1/L2/L3 conformance)
rcan-validate config myrobot.rcan.yaml

# Validate a RCAN message
rcan-validate message command.json

# Verify an audit chain
rcan-validate audit audit.jsonl

# Validate a Robot URI
rcan-validate uri 'rcan://registry.rcan.dev/acme/arm/v2/unit-001'

# Run all checks
rcan-validate all myrobot.rcan.yaml

Spec Compliance

Implements the RCAN protocol — 587 tests, 0 skipped. See the live compatibility matrix for the pinned version this SDK targets.

Covered sections: §1 Robot URI · §2 RBAC · §3 Message Format · §5 Authentication · §5.3 QoS · §6 Safety Invariants · §8.3 Replay Prevention · §8.4 Clock Sync · §8.5 Sender Type · §8.6 Key Lifecycle · §8.7 Level of Assurance · §9 Capabilities · §11 Behavior Scripts · §12 Command Delegation · §13 Revocation · §14 Offline Mode · §16 AI Accountability · §17 Distributed Registry · §18 Federation · §19 Constrained Transport · §21 Registry Integration

Ecosystem

Package	Version	Purpose
rcan-py (this)	v2.0.0	Python SDK
rcan-ts	v2.0.0	TypeScript SDK
rcan-spec	v3.0	Protocol spec
ROBOT.md	v0.1.3	Single-file robot manifest
OpenCastor	v2026.3.17.1	Robot runtime (reference impl)
RRF	v1.6.0	Robot identity registry
Fleet UI	live	Web fleet dashboard
Docs	live	Runtime reference, RCAN, API

Contributing

Issues and PRs welcome at github.com/continuonai/rcan-py.

Spec discussions: github.com/continuonai/rcan-spec/issues

License

MIT