Protocol Comparison: REST vs A2A vs MCP

Suwappu exposes three protocols for interacting with the DEX. All three share the same authentication mechanism and provide access to the same underlying capabilities --- swaps, quotes, portfolio checks, price lookups, and token/chain discovery.

Comparison Table

Feature	REST API	A2A Protocol	MCP Protocol
Transport	HTTP	JSON-RPC 2.0 over HTTP	JSON-RPC 2.0 over HTTP
Endpoint	`/v1/agent/*`	`/a2a`	`/mcp`
Auth	Bearer token	Bearer token	Bearer token
Best for	Direct integration	Agent-to-agent communication	LLM tool use (Claude, etc.)
Discovery	OpenAPI spec	Agent card	`tools/list`
State	Stateless	Task-based (submit -> work -> complete)	Stateless tool calls
Message format	JSON request/response	Natural language in, structured task out	Typed tool calls with JSON schemas
Streaming	No	No (push notifications supported)	No

When to Use Each

REST API

Use the REST API when you are building a traditional integration --- a web app, a backend service, or a script that needs to call specific endpoints directly. You get fine-grained control over each request and predictable response shapes. The OpenAPI spec at /v1/agent/openapi enables code generation in any language.

Good for: Backend services, web frontends, mobile apps, CI/CD pipelines, any code-first integration.

A2A Protocol

Use the A2A (Agent-to-Agent) protocol when you are building an AI agent that communicates with Suwappu as a peer. A2A uses natural language messages and returns structured task objects with lifecycle states. Your agent sends a message like "swap 0.5 ETH to USDC on base" and receives a task that transitions through submitted -> working -> completed.

Good for: Autonomous agents, multi-agent orchestration systems, agent frameworks (LangGraph, CrewAI, AutoGen).

MCP Protocol

Use the MCP (Model Context Protocol) when you are connecting Suwappu to an LLM that supports MCP --- such as Claude Desktop, Claude Code, or any MCP-compatible client. The LLM discovers available tools via tools/list and calls them with typed arguments. No natural language parsing is needed; the LLM handles that.

Good for: Claude Desktop, Claude Code, Cursor, any MCP-compatible LLM client.

Authentication

All three protocols require the same Bearer token. Obtain one by registering:

-kw">curl -X POST https://api.suwappu.bot/v1/agent/register \
  -H -str">"Content-Type: application/json" \
  -d -str">'{
    -str">"name": -str">"my-agent",
    -str">"description": -str">"My trading agent",
    -str">"webhook_url": -str">"https://my class="hl-flag">-agent.example.com/webhook"
  }'

The response includes an api_key (prefixed suwappu_sk_). Use it as a Bearer token in the Authorization header for all subsequent requests, regardless of which protocol you choose:

Authorization: Bearer suwappu_sk_YOUR_KEY

Quick Start by Protocol

Protocol	First request
REST	`GET /v1/agent/quote?from_token=ETH&to_token=USDC&amount=0.5&chain=base`
A2A	`POST /a2a` with `{"method":"message/send","params":{"message":{"role":"user","parts":[{"type":"text","text":"quote 0.5 ETH to USDC on base"}]}}}`
MCP	`POST /mcp` with `{"method":"initialize","params":{}}`, then `tools/list`, then `tools/call`

npm Packages

Package	Description
`@suwappu/mcp-server`	MCP server for Claude Desktop, Claude Code, Cursor (stdio transport)
`@suwappu/sdk`	TypeScript SDK wrapping the REST API
`@suwappu/langchain-suwappu`	LangChain toolkit for building agents with Suwappu tools

Registry Listings

Suwappu is listed on the following agent/tool registries:

Registry	Protocol	Status
awesome-a2a	A2A	Listed (PR #36)
Smithery.ai	MCP	Pending submission
mcpservers.org	MCP	Planned
StackA2A	A2A	Planned
a2aregistry.org	A2A	Registered

Future Registry Submissions

The following registries require manual web form submission:

Smithery.ai — Submit at smithery.ai/new. The smithery.yaml config is already in the repo at packages/mcp-server/smithery.yaml.
mcpservers.org — Submit at mcpservers.org/submit. Also covers the awesome-mcp-servers GitHub list.
mcpserverdirectory.org — Submit at mcpserverdirectory.org/submit.
StackA2A — Submit at stacka2a.dev/submit-agent.
a2aagentlist.com — Email gal6111@gmail.com with agent details.
a2aregistry.org — API registration:

  -kw">curl -X POST -str">"https://a2aregistry.org/api/agents/register" \
    -H -str">"Content-Type: application/json" \
    -d -str">'{-str">"wellKnownURI": -str">"https://api.suwappu.bot/.well class="hl-flag">-known/agent.json"}'

See the individual protocol guides for full details: