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 pricing detail that scales to your verified trust tier.

Endpoints

All buyer-agent traffic is served from agent.hono.com. The public media kit requires no authentication.

Purpose	Path
Agent discovery	`https://agent.hono.com/.well-known/agent.json`
Agent card	`https://agent.hono.com/.well-known/agent-card.json`
MCP transport	`https://agent.hono.com/mcp`
A2A JSON-RPC	`https://agent.hono.com/a2a`
Buyer REST API	`https://agent.hono.com/api/v1`

Protocol support

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

IAB seller-agent surface (MCP)

An IAB-compatible tool set over MCP for browsing inventory, 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.

MCP tools (IAB-compatible set)

Available over the MCP transport at /mcp.

Tool	Purpose
`get_media_kit`	Fetch the publisher's public media kit.
`search_packages`	Search available packages.
`list_products`	List sellable products.
`request_quote`	Request a quote for chosen inventory and terms.
`create_proposal`	Open a proposal on a quote.
`counter_proposal`	Submit a counteroffer during negotiation.
`accept_proposal`	Accept the current terms.
`get_proposal_status`	Check where a proposal stands.
`list_deals`	List your deals with this publisher.
`get_deal`	Fetch a single deal's details.
`get_deal_performance`	Read delivery and performance for a deal.
`register_buyer_agent`	Register your buyer agent to obtain credentials.

AdCP v3 tasks

Media-buy tasks supported alongside the IAB tool set.

Task	Purpose
`get_adcp_capabilities`	Discover supported AdCP capabilities.
`get_products`	Retrieve products for media buys.
`create_media_buy`	Create a media buy.
`update_media_buy`	Update an existing media buy.
`get_media_buys`	List media buys.
`get_media_buy_delivery`	Read delivery for a media buy.
`list_creative_formats`	List accepted creative formats.
`sync_creatives`	Sync creatives for a media buy.

Buyer authentication tiers

Each tier unlocks more pricing detail and negotiation rights. 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.
Seat	Authenticated seat. Unlocks more pricing detail and the ability to request quotes and negotiate.
Agency	Agency-level access. Broader pricing detail and negotiation on behalf of advertisers.
Advertiser	Advertiser-level access. The fullest pricing detail and negotiation rights.

New clients land in pending_review until operator approval. Self-registered buyers start at the lowest tier with pending_review trust; upgrades need verifiable evidence — an IAB Agent Registry lookup, seat confirmation, or operator approval. First deals from low-trust buyers always park for the publisher's human approval.

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, or via OAuth dynamic client registration. New clients start in pending_review.
Get the media kit with get_media_kit and browse inventory with list_products and search_packages.
Request a quote with request_quote for the inventory and terms you want.
Open a proposal with create_proposal, then negotiate using counter_proposal and accept_proposal; track it with get_proposal_status.
On agreement, the deal hands off — via IAB Deals API v1.0 push or seller-executed GAM booking — and you track delivery with get_deal, list_deals, and get_deal_performance.

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 — reach out ahead of integrating so we can set you up. We do not promise live public registry listings yet.