OpenDirect 2.1

OpenDirect 2.1 is IAB Tech Lab’s REST standard for booking guaranteed and reserved advertising inventory: the direct deals that used to move by email and spreadsheet. It defines 23 objects covering accounts, orders, inventory, creative and reporting. It predates agentic buying and defines no agent behaviour.

AAMP is built on it because IAB Tech Lab already owned a ratified object model for the transaction AAMP’s control plane automates, so the agent repositories started from Account, Order, Line and Product rather than inventing four nouns of their own.

The object graph is a booking workflow. Accounts own Orders, Orders hold Lines, Lines book Products. An Assignment attaches a Creative to a Line, and a ChangeRequest amends one already booked. The nesting is in the path: /accounts/{id}/orders/{id}/lines.

Version 1.0 shipped in January 2015 and 2.1 in April 2024. The standard’s page on iabtechlab.com is stamped “last updated 8 July 2024”, lists no implementers and runs no conformance programme, and it does not mention agentic work or AAMP.

AAMP’s inheritance from OpenDirect

seller-agent’s README claims it books “using IAB Tech Lab standards (OpenDirect 2.1, Deals API v1.0, sellers.json)”. buyer-agent lists “REST (OpenDirect 2.1)” as one of three transports, the one for “operator dashboards and legacy integrations”, with MCP as the default. The AAMP hub repository, a README index and a licence file, makes no reference to OpenDirect, OpenRTB or AdCOM.

The copy vendored into agentic-direct keeps the standard’s own metadata block, naming OpenDirect v2.1 Final under Creative Commons Attribution 3.0 and referencing AdCOM, OpenRTB and the DP-AA DOOH Extension, with the example base URL https://opendirect.example.com/v2.1 still in place.

Three implementation subsets

agentic-direct/opendirect.json defines 13 OpenDirect.* schemas, and its 2.1.0 is OpenDirect’s version number rather than its own. (The file is an MCP server manifest, keyed on schemas, tools and resources; the repository’s README describes it as an OpenAPI 3.0 schema and it has no paths key.) iab-agentic-primitives is the schema library both reference agents import, v0.5.0 and unreleased, and it inherits more than the shapes: its Order “merges the buyer’s OpenDirect Order with the seller’s ExecutionOrder”, and its AvailsRequest notes that “spec-named fields use the OpenDirect 2.1 all-lowercase wire names”. seller-agent is the running reference server, 74 OpenAPI paths, and the only one that answers a request. All three are IAB Tech Lab repositories, and none is designated as the one to build against.

The first two columns count schema definitions; the third counts entities with a REST path. AdvertiserBrand, ProductSearch, AvailsStatus, ProductTargeting, ProviderData, Stats, EID and UID appear in none of the three, which is the reporting and identity half of the standard.

The manifest carries Address and Contact but no Avails or search objects; iab-agentic-primitives carries Avails and ProductAvailsSearch but no party-detail objects. Neither body publishes a crosswalk of what survived.

Conformance testing runs to one file. seller-agent/tests/unit/test_opendirect_wire_conformance.py covers a single endpoint, POST /products/avails, and what it pins is spelling: productid, startdate and enddate have to parse under their lowercase spec names, and the camelCase aliases must not be accepted or emitted. It pins lowercase because the source document ships both: OpenDirect’s Account attribute table is all lowercase, while the normative /accounts example returns “Accounts”, “AdvertiserId” and “Id” in PascalCase, plus an AgencyId the table never defines. Three of that endpoint’s six request fields are spec-named; requestedImpressions, budget and targeting have, the docstring says, “no spec name to converge to”.

What OpenDirect does not define

Negotiation, quote, access tier, trust status, agent card and embedding appear nowhere in the standard, which is why 14 of the 22 core primitives in iab-agentic-primitives have no OpenDirect ancestor by name, Agent, Quote, Negotiation and MediaKit among them.

Inheriting the standard also carried a cost on money typing. OpenDirect 2.1 carries price as a decimal float. iab-agentic-primitives numbers its contested design calls in the schema descriptions, and FD-11 bans float money on the wire, because binary floating point cannot hold decimal money exactly; the ban is an executable check in src/iab_agentic_primitives/conformance/standards.py. Across four Avails schemas, price “stays a float per the OpenDirect 2.1 decimal dialect”.

OpenDirect and AdCP

AdCP’s published docs and schema registry never mention OpenDirect, while naming IAB Tech Lab in dozens of files and referencing OpenRTB, AdCOM and VAST throughout. Its documentation tooling does index the OpenDirect repository, alongside roughly 28 others; the objects AdCP publishes are defined independently of it.

Media Buy and Package are where Order and Line went, and the two stacks line up object by object on the terminology lookup.

Common confusions

OpenDirect and OpenRTB do not sit in the same plane. OpenDirect belongs to AAMP’s control plane, where a human would once have signed an insertion order; OpenRTB 2.6 belongs to the agentic RTB framework at serve time, imported as com/iabtechlab/openrtb/v2.6/openrtb.proto. AAMP is credited to “OpenRTB, AdCOM and OpenDirect”, three inheritances in three different planes, and the full stack comparison separates them.