> ## Documentation Index > Fetch the complete documentation index at: https://docs.apostra.com/llms.txt > Use this file to discover all available pages before exploring further. # What a great sales agent does > The three steps a sales agent climbs on Apostra, transact, sell well and premium, ordered by the buyer demand each one opens, with how Apostra checks each step and what has a date. A sales agent on Apostra does more than list products. Buyers book it, send it creatives, read its reporting, send it briefs and pay more for what only it can sell. This page puts all of that in order: three steps, each opening more buyer demand than the one before. Finish the first before you start the second. The [Agent page](https://docs.apostra.com/v3/connect-an-agent.md#see-where-each-agent-stands) lists every check your agent has passed or not passed yet. This page says which of those checks belong to which step, so you can work on the step you are on. | Step | What buyers get | Where to read the detail | | - | - | - | | 1. Transact | They can book your agent, run creatives on it, and trust its numbers | [Sales agent checklist](https://docs.apostra.com/v3/seller-agent-checklist.md), then [Certification](https://docs.apostra.com/v3/certification.md) | | 2. Sell well | Your agent answers their briefs and targets their audiences, at a price | [Agent requirements](https://docs.apostra.com/v3/agent-requirements.md) | | 3. Premium | Formats and buys only your agent can offer | The sections linked under step 3 | Briefs matter more than most agents expect. In the 90 days to 13 November 2026, more than half of the requests buyers on Apostra sent to sellers were briefs, asking for a plan, rather than browsing a catalog. An agent that serves only a catalog can be booked, but it never answers those briefs. ## Step 1: transact **Buyers can book your agent and trust what it reports.** Without this step, a buyer on Apostra cannot buy from you at all: Apostra sends new buys to a sales agent only for the use cases it has passed. See [The certification deadline](https://docs.apostra.com/v3/certification.md#the-certification-deadline). What your agent does: * **Declares what it is and what it sells.** The [sales agent checklist](https://docs.apostra.com/v3/seller-agent-checklist.md) is the short list to work through before you connect. * **Takes, changes and cancels buys,** and answers status reads for every buy. See [Takes buy corrections](https://docs.apostra.com/v3/agent-requirements.md#takes-buy-corrections) and [Answer status reads for every buy](https://docs.apostra.com/v3/agent-requirements.md#answer-status-reads-for-every-buy). * **Accepts the buyer's creatives, with their macros and trackers.** Apostra's trackers are how a buyer checks that an ad ran. See [Accept the creatives your formats declare](https://docs.apostra.com/v3/agent-requirements.md#accept-the-creatives-your-formats-declare) and [Creatives sent before a buy](https://docs.apostra.com/v3/agent-requirements.md#creatives-sent-before-a-buy). * **Reports delivery on time,** by package and by creative, so buyers can pace and pay. See [Report each creative's own delivery](https://docs.apostra.com/v3/agent-requirements.md#report-each-creatives-own-delivery) and [Deliver reporting to Apostra](https://docs.apostra.com/v3/seller-reporting-delivery.md). * **Signs the webhooks it sends.** See [Signing the webhooks you send us](https://docs.apostra.com/v3/seller-webhook-signing.md). How Apostra checks it: certification places small test buys and judges each use case that applies to your products, for example display with our tag, or VAST video with our trackers. See [Use cases](https://docs.apostra.com/v3/certification.md#use-cases). What has a date: canonical creative formats, Reliable Reporting and webhook signing each become required on a date. The [schedule](https://docs.apostra.com/v3/adcp-4-readiness.md#the-schedule) has the dates and what an agent that misses them loses. ## Step 2: sell well **Your agent wins the briefs buyers send, at the right price.** A buyer who can only pick from a catalog buys less than one who can describe a campaign and get a plan back. What your agent does: * **Answers briefs as well as selling from a catalog.** Declare the buying modes you serve. See [Declare your buying modes](https://docs.apostra.com/v3/agent-requirements.md#declare-your-buying-modes). * **Prices and forecasts honestly,** and keeps one opportunity together across a negotiation. See [Keep one opportunity together](https://docs.apostra.com/v3/agent-requirements.md#keep-one-opportunity-together). * **Honours the targeting it declares,** including the property lists buyers send. See [Declare the targeting you honour](https://docs.apostra.com/v3/agent-requirements.md#declare-the-targeting-you-honour) and [Resolve the property lists we send](https://docs.apostra.com/v3/agent-requirements.md#resolve-the-property-lists-we-send). * **Sells audiences:** your own, priced, and the buyer's own, synced to you. See [Declare how audiences reach you](https://docs.apostra.com/v3/agent-requirements.md#declare-how-audiences-reach-you) and [Finding and buying a storefront's signals](https://docs.apostra.com/v3/storefront-signals.md). * **Takes conversions,** so buyers can buy toward outcomes. How Apostra checks it: the use cases for audience or signal targeting, CPA and conversion tracking, and cost per completed view, and the compact lifecycle. See [Use cases](https://docs.apostra.com/v3/certification.md#use-cases). What has a date: the compact lifecycle becomes required on the date in the [schedule](https://docs.apostra.com/v3/adcp-4-readiness.md#the-schedule). ## Step 3: premium **Buyers pay more for what only you have.** High-impact formats, newsletters, podcasts and sponsored posts, deals, and guaranteed buys are where brand budgets go. What your agent does: * **Declares those products in their own channels and formats,** so buyers can find them. See [Declare AdCP channels on every Product](https://docs.apostra.com/v3/agent-requirements.md#declare-adcp-channels-on-every-product). * **Sells guaranteed buys against real availability.** See [Guaranteed buys over the ad server forecast](https://docs.apostra.com/v3/seller-guaranteed-availability.md). How Apostra checks it: a format Apostra's tracker cannot measure is checked with a seller-reported sandbox buy. See [Use cases](https://docs.apostra.com/v3/certification.md#use-cases). What has a date: nothing in this step. ## You do not have to build every step yourself * **Use an AdCP SDK.** The SDKs at [docs.adcontextprotocol.org](https://docs.adcontextprotocol.org) handle declarations, webhook signing and the buy lifecycle, so you build what is specific to your business. * **Let Apostra's agent sell for you.** If you would rather not run a sales agent, sell with a Storefront: an agent Apostra hosts answers buyers inside your prices and rules. See [Sell on Apostra](https://docs.apostra.com/v3/sell-on-apostra.md). * **Work with a partner.** A certified partner's agent can sell for you. See [Certified, exempt and beta partner agents](https://docs.apostra.com/v3/seller-partner-agent-certification.md). ## Related * [Sales agent checklist](https://docs.apostra.com/v3/seller-agent-checklist.md): what to declare before you connect. * [Agent requirements](https://docs.apostra.com/v3/agent-requirements.md): every check, and how to fix a finding. * [Certification](https://docs.apostra.com/v3/certification.md): how an agent is tested and kept certified. * [Getting ready for AdCP 4.0](https://docs.apostra.com/v3/adcp-4-readiness.md): what becomes required, and when. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.