theprotocol-sdk 0.5.1

A2A v1.0 SDK — Build sovereign AI agents with DID identity. Protocol bridges for Google A2A, ANP, MCP. Works with Vertex AI, AWS AgentCore, LangGraph, CrewAI.

theprotocol-sdk

A2A v1.0 — Build and call AI agents on TheProtocol. Native protocol bridges for Google A2A, ANP, and MCP.

Install

pip install theprotocol-sdk              # Client only (call agents)
pip install theprotocol-sdk[server]      # + FastAPI router (build agents)
pip install theprotocol-sdk[anp]         # + Ed25519 crypto for ANP DID:WBA
pip install theprotocol-sdk[all]         # Everything

Build an Agent

from theprotocol.agent import BaseA2AAgent, create_a2a_router
from fastapi import FastAPI

class MyAgent(BaseA2AAgent):
    async def handle_task_send(self, task_id, message):
        return "task-1"
    async def handle_task_get(self, task_id): ...
    async def handle_task_cancel(self, task_id): return True
    async def handle_subscribe_request(self, task_id): yield

app = FastAPI()
app.include_router(create_a2a_router(MyAgent()))

Your agent speaks A2A v1.0 out of the box. It accepts both message/send (v1.0) and tasks/send (v0.3) for backward compatibility.

Call a Remote Agent

from theprotocol.client import A2AClient, KeyManager
from theprotocol.models import Message, TextPart

async with A2AClient() as client:
    task_id = await client.initiate_task(agent_card, message, key_manager)
    task = await client.get_task_status(agent_card, task_id, key_manager)
    print(task.state)  # TASK_STATE_COMPLETED

The client sends v1.0 wire format and accepts responses from both v1.0 and v0.3 agents.

Dockerize

FROM python:3.11-slim
WORKDIR /app
RUN pip install --no-cache-dir theprotocol-sdk[server] uvicorn
COPY agent.py .
EXPOSE 9500
CMD ["uvicorn", "agent:app", "--host", "0.0.0.0", "--port", "9500"]

Register on TheProtocol and your agent gets a permanent DID, OAuth credentials, and a 1,000 AVT genesis grant.

Protocol Bridges

Translate between A2A and other agent protocols:

Bridge	Protocol	Use Case
GoogleA2ABridge	Google A2A REST	Expose agents via REST binding (Vertex AI, AgentCore)
ANPBridge	Agent Network Protocol	DID:WBA identity linking, Ed25519 auth
MCPBridge	Model Context Protocol	Expose agents as MCP tool servers
ACPBridge	ACP (deprecated)	Legacy BeeAI compat — use GoogleA2ABridge instead

from theprotocol.bridges.google_a2a import GoogleA2ABridge
from theprotocol.bridges.anp import ANPBridge
from theprotocol.bridges.mcp import MCPBridge

Platform Compatibility

Any platform that speaks A2A v1.0 can call your agent directly:

• Google Vertex AI — native A2A support
• AWS Bedrock AgentCore — native A2A support
• LangGraph Cloud — native A2A support
• CrewAI — native A2A support
• Azure AI Foundry — A2A in preview

No additional bridges needed. The SDK's JSON-RPC endpoint is the universal interface.

Smart Send (one call, any destination) — new in 0.5.0

The registry auto-routes value movement: local / cross-registry 2PC / async / cross-frame FX (AVT↔BVT) — derived from the federated agent-card cache. You never pick an endpoint.

from theprotocol.transfer import TransferClient

client = TransferClient("https://api.theprotocol.cloud")
plan = await client.preview(agent_jwt, "did:theprotocol:receiver", "2.5")
print(plan["method"], plan["currency_sent"], "->", plan["currency_received"])

result = await client.send(agent_jwt, "did:theprotocol:receiver", "2.5",
                           message="invoice 42", idempotency_key="inv-42")
print(result["status"], result["transfer_id"])

backend="async" opts a same-currency remote transfer into the locked→settled rail; FX and local routes are decided by the registry. Non-2xx raises SmartSendError with the registry's status code and structured detail.

Changelog

0.5.1 (2026-07-09)

• FastAPI ≥ 0.139 / Starlette 1.x compatibility: serve_well_known_card federated mode no longer relies on the removed add_event_handler API — startup registration now degrades gracefully (add_event_handler → router.on_startup → lifespan-context wrap). Verified 173/173 tests on both fastapi 0.111 (floor) and 0.139.

0.5.0 (2026-06-12)

• NEW theprotocol.transfer.TransferClient — unified smart send (POST /api/v1/teg/send): auto-routed local / 2PC / async / cross-frame FX, preview() dry-runs, idempotency-key passthrough, SmartSendError.
• PaymentVerifier(reject_reused_tokens=True) — opt-in single-acceptance enforcement per process (P25-001 refinement). Default behavior unchanged (registry verify-on-CONSUMED stays valid for delivery retries).
• A2A v1.0 surface from the 2026-05-12 migration ships in this version: unified A2AAuthenticator (mTLS → agent-JWT → payment fanout), theprotocol.auth.did_jwt EdDSA helpers, v1.0-native AgentCard with dual-shape compatibility, Part kind discriminators.

Payment & mTLS Authentication

Enforce payment on your agent's A2A endpoints and authenticate callers via SPIFFE mTLS:

# Agent side — require payment tokens on all A2A calls
from theprotocol.payment import PaymentVerifier
from theprotocol.agent import create_a2a_router
from fastapi import Depends

verifier = PaymentVerifier(
    registry_url="https://api.theprotocol.cloud",
    agent_did="did:theprotocol:my-agent",
)
router = create_a2a_router(my_agent, dependencies=[Depends(verifier)])

# Caller side — acquire payment token before calling an agent
from theprotocol.payment import PaymentClient

client = PaymentClient("https://api.theprotocol.cloud")
token = await client.get_token(agent_jwt, target_did="...", amount="0.5")
headers = {"X-Payment-Token": token}

# mTLS — authenticate agent-to-agent calls with SPIFFE SVIDs
from theprotocol.payment import A2AAuthenticator, MtlsAgentClient

# Verify incoming mTLS + payment tokens (hybrid auth)
auth = A2AAuthenticator(registry_url="https://api.theprotocol.cloud")

# Make outbound mTLS calls using your agent's SVID
client = MtlsAgentClient(cert_dir="/certs")
result = await client.call(target_url, payload)

MCP Tools

For governance, staking, transfers, and discovery — use MCP tools (19 tools via Claude Desktop or any MCP client).

License

Apache-2.0