Nats Agent Fabric

NATS Agent Fabric (Synadia Agent Protocol)

Build AI agents that register on a NATS bus, get discovered by callers, and stream replies — using the Synadia Agent Protocol for NATS and the Synadia Agents SDK.

The core idea: most agent libraries assume one process and one known endpoint. This protocol is built for the opposite shape — many agents, across many harnesses/runtimes/clouds, none known to the caller in advance. An agent is just a function from a prompt to a streamed reply (onPrompt); only the body differs. Agents register as ordinary NATS micro-services, so they inherit NATS accounts (multi-tenancy/isolation), cloud-to-edge connectivity, and a message-level audit trail "for free."

This is agent-to-agent coordination, not MCP — MCP standardizes tools/context for one agent; this standardizes discovery + transport across many agents on a shared bus. It is LLM-agnostic: it wraps harnesses (Claude Code, a DSPy ReAct loop, your own LLM service), not models.

Maturity note (read before quoting versions)

The protocol spec is v0.3 and the 0.x line is explicitly unstable. Package versions as of mid-2026: npm @synadia-ai/agents and @synadia-ai/agent-service at 0.5.2; PyPI synadia-ai-agents (~0.6) and synadia-ai-agent-service 0.4.1. Go SDK is planned, not released — for Go today, implement the wire protocol directly over nats.go micro (see examples/protocol-go.md).

Because SDK APIs may drift inside 0.x, teach the protocol (stable) and treat exact constructor/method names as current-but-verify. When generating code, tell the user to confirm the installed package version. The wire protocol is the durable contract that all SDKs and hand-rolled agents must honor.

When to defer to the JetStream skills

This skill is built on the NATS Services API (micro), not core JetStream — discovery, registration, and request/reply all use $SRV.* + queue groups. JetStream and KV enter the picture only for durable agent state and session handoff (roadmap / optional), covered in patterns/durable-state.md.

• Designing the underlying streams/KV buckets that back durable agent memory → also read jetstream-architecture.
• Deploying the NATS servers/accounts your agents connect to → jetstream-deployment.
• Monitoring, troubleshooting, or tuning the running fabric → jetstream-operations.

Reference Files

Read these as needed — don't load all of them upfront:

• concepts/protocol.md — the wire protocol: subject hierarchy, the four verbs, service registration rules, request envelope, response chunk types, stream termination, heartbeats, discovery, errors, versioning. Read this before writing any agent or caller, in any language — it's the contract.
• concepts/architecture.md — caller (client) SDK vs host (agent) SDK, meta-agent vs worker shape, queue-group load-balancing, identity (agent/owner/name/session), and where JetStream/KV fit. Read when deciding what to build.
• patterns/meta-agent.md — discover → fan-out → merge, liveness tracking without polling, and human-in-the-loop mid-stream queries. Read when building an orchestrator.
• patterns/durable-state.md — using JetStream + KV for agent memory and session handoff. Read when agents need to remember or hand off work.
• examples/typescript.md — caller + host with @synadia-ai/agents / @synadia-ai/agent-service. Read for TS/Node/Bun code.
• examples/python.md — caller + host with synadia-ai-agents / synadia-ai-agent-service. Read for Python code.
• examples/protocol-go.md — a protocol-compliant agent in Go over nats.go micro (no SDK yet). Read for Go, or any language without an SDK.

Workflow

Step 1: Figure out which side they're building. Host an agent (make my agent discoverable/promptable)? Call agents (orchestrate/meta-agent)? Or both? See concepts/architecture.md.

Step 2: Pick the language path. TS and Python have SDKs; Go and everything else implement the protocol directly. If they have no SDK for their language, route to examples/protocol-go.md as the template.

Step 3: Read concepts/protocol.md for the exact subjects, envelope, and chunk format — get these right regardless of SDK, because they're what makes agents interoperate.

Step 4: Implement. For hosts: register as service name agents, serve the prompt endpoint on a queue group, emit heartbeats. For callers: discover via $SRV, prompt, consume the typed chunk stream until the zero-byte terminator.

Step 5: If agents need memory or handoff, layer in JetStream/KV per patterns/durable-state.md.

Step 6: Wire identity and isolation — pick stable agent/owner/name tokens and use NATS accounts for tenant separation (defer infra to jetstream-deployment).

Core Principles

• Honor the wire protocol exactly — service name MUST be agents, the prompt endpoint MUST use queue group agents, every response stream MUST start with a {"type":"status","data":"ack"} chunk and MUST end with a zero-byte message and no headers. These are what let a caller talk to an agent it has never seen.
• Never construct endpoint subjects from identity (except the heartbeat subject agents.hb.{agent}.{owner}.{name}, which is fixed). Learn endpoints from the discovery ($SRV.INFO.agents) response — addressing is discovery-driven by design.
• Discovery first, not hardcoded endpoints — the whole point is that callers don't know agents in advance. Use $SRV.PING.agents / $SRV.INFO.agents.
• Stream, don't block — replies are a stream of typed chunks (response, status, query), consumed as an async iterator. Surface tokens as they arrive.
• Forward-compatibility is mandatory — callers MUST silently ignore unknown chunk types and preserve unknown fields. The 0.x protocol will add types; don't crash on them.
• Use queue groups for horizontal scale — multiple instances of the same agent share the agents queue group so prompts load-balance across them automatically.
• Heartbeat for liveness — emit to agents.hb.* every ~30s; treat an agent offline after 3× missed intervals. Use the status request/reply endpoint to bootstrap liveness without waiting for the next beat.
• Identity is agent/owner/name(/session) — choose stable, lowercase tokens (a–z 0–9 - _), never starting with $. These compose the subject namespace and the discovery metadata.
• Isolate tenants with NATS accounts, not application logic — multi-tenancy comes from the bus, not your code.
• Durable state is JetStream/KV, and it's optional — v0.3 transport is stateless micro; reach for streams/KV only when agents need memory or handoff.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: lithqube
• Source: lithqube/nats-jetstream-claude-skills
• License: MIT

Install and usage instructions live in the source repository linked above.