Core concepts

API (a.k.a. tool)

A single HTTP endpoint registered on Blue Agent. Each one has:

• A unique slug (e.g. honeypot-check) — how it appears in URLs and code.
• An input schema — the JSON fields the endpoint expects.
• A price in USDC per call (0 = free, max $100).
• A provider — the wallet/agent that owns it and receives 80% of revenue.
• A verified badge (Blue Agent reviewed) and an AI Ready badge (returns structured JSON).

You'll see them called "APIs" on the marketplace and "tools" from the MCP perspective — same thing, different framing depending on whether you're a human browsing or an AI calling.

Provider

The agent, team, or solo developer who registered an API. Identified by a Base wallet address and a public handle. Providers see their APIs, lifetime calls, and accrued USDC in the dashboard.

Today: Blue Agent is the seed provider (50 first-party APIs). Aeon and MiroShark have reserved slots. Anyone else can register and become a provider.

MCP — Model Context Protocol

The open standard that lets AI clients (Claude Desktop, Cursor, Cline, custom agents) discover and call external tools. Blue Agent runs one MCP server at:

https://blueagent.dev/api/mcp

Add that URL to your client config (see Install MCP) and every API in the marketplace appears as a callable tool. tools/list returns them all — including community-submitted ones, automatically.

Protocol: JSON-RPC 2.0 over Streamable HTTP (MCP spec 2025-03-26). Supports both application/json and SSE response shapes via the Accept header.

x402 — pay-per-call HTTP

The payment protocol. Server returns HTTP 402 Payment Required with USDC instructions, client signs an EIP-3009 TransferWithAuthorization once, retries with the X-Payment header — done in sub-second.

Why it matters: no accounts, no API keys, no minimum balance. Autonomous AI agents can call APIs without a human approving each transaction — the wallet just signs the payment as part of the request.

Full walkthrough: x402 payment flow.

Credits

Free-tier allowance for calling APIs without paying USDC per call. Two ways to earn:

• Guest — 30 credits/day, no wallet needed (IP-rate-limited).
• Holder — hold or stake $BLUEAGENT for tiered allowance (500 / 2,000 / ∞ per day).

Credits cover one call to most tools — heavier tools may cost multiple credits. For high-volume use, paying x402 USDC per call removes the daily cap entirely.

Putting it together

The simplest flow, end-to-end: a provider registers an API → any AI client speaking MCP discovers it via tools/list → calls it → server returns x402 402 → client signs USDC payment → provider gets paid (80% builder, 20% Hub).