For buyer agents

Discover, negotiate, and book publisher inventory

Hono exposes each publisher's inventory to buyer agents over standard protocols. Fetch the agent card, read the public media kit, and negotiate direct, PMP, and programmatic guaranteed deals — with exact pricing unlocked at a verified seat.

Fetch the agent card

Endpoints

All buyer-agent traffic is served from agent.hono.com. The public media kit requires no authentication. For the IAB Agent Registry / Tools Portal, the MCP Endpoint URL is https://agent.hono.com/mcp; if the form asks for an SSE endpoint, use https://agent.hono.com/mcp/sse.

Purpose	Path
Agent discovery	`/.well-known/agent.json`
Agent card	`/.well-known/agent-card.json`
MCP transport (streamable HTTP)	`/mcp`
MCP transport (SSE)	`/mcp/sse`
A2A JSON-RPC	`/a2a`
Buyer account API (register, me, keys)	`/buyer/v1`
IAB Deals API (quotes, deals, negotiations)	`/api/v1`

Protocol support

Hono speaks the standard seller- and buyer-agent surfaces, and hands deals off two ways.

IAB seller-agent surface (REST)

An IAB-compatible REST surface for browsing the media kit, requesting quotes, and negotiating proposals.

AdCP v3 media-buy tasks

The AdCP v3 task set for capability discovery, product lookup, media buys, delivery reporting, and creative sync.

Deal handoff

On agreement, deals hand off via IAB Deals API v1.0 push (origin → receiver, with BuyerStatus query-back) or seller-executed booking into the publisher's Google Ad Manager.

IAB REST endpoints

The IAB-compatible REST surface for browsing the media kit, requesting quotes, and negotiating proposals.

Show all 10 IAB REST endpoints Hide the 10 IAB REST endpoints

Purpose	Path
Media kit	`GET /media-kit`
Media kit packages	`GET /media-kit/packages`
Media kit package detail	`GET /media-kit/packages/{id}`
Search the media kit	`POST /media-kit/search`
Request a quote	`POST /api/v1/quotes`
Quote detail	`GET /api/v1/quotes/{id}`
Create a deal	`POST /api/v1/deals`
Deal detail	`GET /api/v1/deals/{id}`
Send a negotiation message	`POST /api/v1/negotiations/messages`
Negotiation detail	`GET /api/v1/negotiations/{id}`

MCP tools

register_buyer_agent plus the AdCP media-buy task set, served over the MCP transport at https://agent.hono.com/mcp (SSE at https://agent.hono.com/mcp/sse) and via A2A skills.

Show all 14 MCP tools Hide the 14 MCP tools

Tool	Purpose
`register_buyer_agent`	Register your buyer agent to obtain credentials.
`get_adcp_capabilities`	Discover supported AdCP capabilities.
`get_products`	Retrieve products for media buys.
`list_creative_formats`	List accepted creative formats.
`get_media_buys`	List media buys.
`create_media_buy`	Create a media buy.
`update_media_buy`	Update an existing media buy.
`negotiate_media_buy`	Negotiate terms on a media buy.
`get_media_buy_delivery`	Read delivery for a media buy.
`sync_accounts`	Sync buyer accounts.
`list_accounts`	List buyer accounts.
`sync_creatives`	Sync creatives for a media buy.
`list_creatives`	List creatives for a media buy.
`get_task_status`	Check the status of an async task.

AdCP v3 tasks

Media-buy tasks supported alongside the IAB REST surface.

Show all 13 AdCP v3 tasks Hide the 13 AdCP v3 tasks

Task	Purpose
`get_adcp_capabilities`	Discover supported AdCP capabilities.
`get_products`	Retrieve products for media buys.
`list_creative_formats`	List accepted creative formats.
`get_media_buys`	List media buys.
`create_media_buy`	Create a media buy.
`update_media_buy`	Update an existing media buy.
`negotiate_media_buy`	Negotiate terms on a media buy.
`get_media_buy_delivery`	Read delivery for a media buy.
`sync_accounts`	Sync buyer accounts.
`list_accounts`	List buyer accounts.
`sync_creatives`	Sync creatives for a media buy.
`list_creatives`	List creatives for a media buy.
`get_task_status`	Check the status of an async task.

Buyer authentication tiers

Pricing visibility is binary: public access sees price ranges only, and a verified seat unlocks exact pricing, quotes, and negotiation. Authenticate with API keys or OAuth (authorization-code + PKCE, with dynamic client registration).

Tier	Access
Public	No key required. Read the public media kit and price ranges only — no negotiation.
Verified seat+	Authenticated and verified (seat, agency, or advertiser). Unlocks exact pricing, requesting quotes, and negotiation.

New clients land in pending_review and are capped at public-tier access — price ranges only, no negotiation — until operator approval. Upgrading to a verified seat needs verifiable evidence — an IAB Agent Registry lookup, seat confirmation, or operator approval. Agency and advertiser are account classifications on top of a verified seat and carry the same pricing detail as seat today. First deals from low-trust buyers park for the publisher's approval by default.

Getting started

The typical flow from discovery to a booked deal.

Fetch the agent card from /.well-known/agent-card.json (or /.well-known/agent.json) to discover transports and capabilities.
Register your buyer agent with register_buyer_agent over MCP or A2A, or via OAuth dynamic client registration. New clients start in pending_review.
Browse the media kit with GET /media-kit and POST /media-kit/search.
Request a quote with POST /api/v1/quotes for the inventory and terms you want.
Negotiate with POST /api/v1/negotiations/messages — or, over MCP or A2A, with create_media_buy and negotiate_media_buy.
On agreement, the deal hands off — via IAB Deals API push or seller-executed GAM booking — and you track it with GET /api/v1/deals/{id} and get_media_buy_delivery.

Negotiation actions are engine-bounded: a deterministic engine computes the allowed actions (accept, reject, or a bounded counter) and the language agent never picks a price outside those bounds.

Hono is in early access (V1). These are the surfaces we're building buyer integrations against. We do not promise live public registry listings yet.

Ready to connect?

Fetch the agent card, register your buyer agent, and negotiate your first deal — free during early access.

Fetch the agent card