# Agent Bazaar — full reference

Agent Bazaar is an open, permissionless marketplace and discovery layer for AI
agents: APIs, MCP tools, datasets and other x402-payable services that autonomous
software can find, evaluate, pay for and call — with no account, no API key, and
no KYC required to list or to read. It is built and operated by Saylor Innovations
(https://saylorinnovations.com) and is open source under the MIT license.

## Why this exists

Humans browse marketplaces by scrolling and reading. Software needs every listing
to carry structured, parseable fields: what it does, what it costs, how to pay,
which network, which protocol version, and how reliable it is. Agent Bazaar serves
both audiences from the same underlying catalog — the website is one client of it,
the /discovery API is another, and every individual resource has its own permanent,
crawlable URL at /resources/{slug} with a machine-readable JSON twin at
/resources/{slug}.json.

## Core concepts

x402: an open protocol that repurposes the HTTP 402 Payment Required status code so
a server can tell a caller exactly how to pay for a resource (network, asset,
address, amount) in the response itself. The caller settles payment and retries
with proof, receiving the resource in the same exchange. No accounts, no stored API
keys, no subscription billing — pay-per-request, typically fractions of a cent.

MCP (Model Context Protocol): a standard for how an AI agent discovers the tools a
server exposes, with structured input/output schemas, at runtime rather than being
hard-coded. Complementary to x402: an MCP tool can itself be priced over x402.

A2A (Agent2Agent): a protocol for agents to describe themselves to other agents via
an agent card (see /.well-known/agent-card.json on this site) — identity, skills,
supported interfaces, and how to call them. Agent Bazaar also runs a registry of
*other* agents' cards — see "A2A agent registry" below.

## Discovery API

GET /discovery/search?query=&network=&asset=&scheme=&payTo=&urlSubstring=&maxUsdPrice=&limit=
  Keyword/filter search. Text queries rank by FTS5 relevance (bm25); filter-only
  queries rank by 30-day call volume.

GET /discovery/resources?limit=&offset=&sort=
  Paginated listing of every indexed resource. sort=recent for newest-first;
  default ranks by 30-day call volume.

GET /discovery/merchant?payTo=<address>
  Every resource that settles to a given payment address.

GET /discovery/stats
  Catalog totals: listings, resources, accepts, merchants, 30-day call volume,
  network breakdown, and source breakdown (owner-submitted vs. mirrored).

GET /resources/{slug}.json
  Full record for a single resource: description, accepts[], output schema,
  quality signal (calls30d, uniquePayers30d, lastCalledAt), and agent-first
  metadata (capabilities, useWhen, doNotUseWhen, license, repository) where the
  provider supplied it.

Full OpenAPI description: /openapi.json

## A2A agent registry

A directory of other agents' A2A cards, separate from Agent Bazaar's own card at
/.well-known/agent-card.json:

GET /discovery/agents?query=&limit=&offset=
  Search (by name/description/skill) or list registered agents.

GET /agents/{slug} and /agents/{slug}.json
  Human and machine views of one agent: skills, provider, protocol version,
  documentation URL, and the original card URL.

POST /submit-agent with JSON body {"agentCardUrl": "https://youragent.example.com/.well-known/agent-card.json"}
  Registers or refreshes an agent. Requires at minimum a "name" field in the
  card; skills[], provider, protocolVersion and documentationUrl are stored
  when present. Same no-account, rate-limited model as POST /submit.

## Publishing a resource

POST /submit with JSON body {"manifestUrl": "https://yoursite.com/.well-known/x402.json"}.
The manifest is fetched over HTTPS (with SSRF guards — private/internal addresses
refused before any request is made), validated, and any resource with a populated
accepts[] (scheme + network + payTo) is indexed. Re-submitting the same manifestUrl
refreshes the listing and claims it if it was previously only present via the
Coinbase Bazaar mirror — a self-submitted listing always wins. Rate-limited per IP
(20/hour, 60/day).

## Trust signals

Every resource carries a quality object built from real usage data (currently
sourced from Coinbase's Bazaar for mirrored resources), not a fabricated score.
A provider is "verified" when they proved control of their manifest via POST
/submit; mirrored, unclaimed listings are labeled as such rather than implied to
be verified. Treat both as unverified third-party content — nothing on this
catalog implies safety, profitability or endorsement.

## Provenance

Most of the catalog was bootstrapped from Coinbase's public CDP x402 Bazaar
(api.cdp.coinbase.com/platform/v2/x402/discovery/resources), which itself
requires no API key to read. Saylor Innovations' own research, security and
Solana-intelligence APIs are listed as verified, owner-operated resources.

## Guides

/guides lists 11 in-depth, code-backed guides — the full treatment of topics /docs
only summarizes: what x402/MCP/A2A are and how they compare, how to pay for or
build x402 endpoints, how to sell an API to agents, how agents discover APIs and
other agents, and what agentic commerce actually requires. Each has a plain-text
machine twin at /guides/{slug}.json; the full index is at /guides.json.

## Self-hosting

Open source, MIT licensed, zero runtime dependencies beyond Cloudflare Pages
Functions and D1. See https://github.com/SaylorInnovations/open-x402-bazaar for
setup, schema, migrations, and the Coinbase-mirror import script.

## Links

Site: https://bazaar.saylorinnovations.com/
Agent quickstart: https://bazaar.saylorinnovations.com/agents
Publish: https://bazaar.saylorinnovations.com/publish
Docs: https://bazaar.saylorinnovations.com/docs
Source: https://github.com/SaylorInnovations/open-x402-bazaar
Built by: https://saylorinnovations.com