> ## 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. # Open Media Partners > Open the buyer's unified media-partner catalog, actions, and advertiser activation view The Media Partners page and the public V3 `seller`/`connection` nouns plus `save_connection` are available to every buyer account. An Apostra-provisioned signup sandbox is the narrow exception: its verified Agent Registration receives the reversible setup contract, including unmap and remove, but not seller selection, billing, feature-policy, or spend authority. `open_connections_page` launches **Media Partners** — the buyer's unified catalog for Global Market Makers, Regional Market Makers, and Marketplace sellers. The buyer interface calls these commercial counterparties **media partners**; the public API keeps the `seller` noun and `sellerId` fields. The page shows only sales sources: creative, signal, measurement, optimization, and composite agents belong on their own surfaces. It opens on **Ready for buying**; choose **All** to include media partners that are not open for buying yet. The page keeps marketplace classification, marketplace readiness, account-wide selection, required action, and per-advertiser activation separate. It is a **widget launcher**: the tool accepts optional positive integer-string `advertiserId` and `sellerId` seeds. Omit both for the account overview. Pass `connectionAction: "connect"` with `sellerId` to open that seller's connection setup. The launcher itself is read-only; authorization begins only after the buyer confirms in the widget. The launcher returns only a UI resource directive plus the supplied seeds, and the page then self-fetches its own data. It is buyer-only; writes remain limited to the page's host-authorized seller, connection, billing, and mapping operations. A **seller** is the API noun for a media partner: one exact Storefront that can be discovered and selected even before it is connected. A **connection** is one buyer-account authorization grant to that seller. One seller can therefore have zero, one, or several connections. Each connection can expose several provider accounts (for example, child ad accounts under one authorized business manager); those accounts are detail inside the connection, not additional seller or connection nouns. ## Advertiser availability Media Partners evaluates seller-managed availability from an advertiser's country scope and channels. When the country scope is unknown or no channel is selected, the advertiser view pauses before showing media partners and offers one advertiser setup action. A confirmed empty country list means the advertiser has no country qualifier; it is a complete scope and does not block Media Partners. It also contributes no regional market match. A legacy advertiser whose country scope is unknown can set that scope once from **Edit advertiser**. The setup prompt is not repeated on each media partner card. Direct ad-platform connections do not trigger this requirement because their availability does not depend on the advertiser's country scope and channels. Once setup is complete, a Regional Market Maker that does not cover the advertiser's markets explains the mismatch and offers **Add media partner** when an account-level override is available. ## From an agent (MCP) Ask in natural language — "show my media partners", "set up my connection to Meta", "connect Google Ads", or "map this account to an advertiser" — and the agent calls `open_connections_page` after resolving the seller when necessary. Omit `advertiserId` to open the account overview: ```json theme={null} { "name": "open_connections_page", "arguments": {} } ``` When the user is working with a known advertiser, pass its numeric id as a string to open Media Partners in that advertiser's scope: ```json theme={null} { "name": "open_connections_page", "arguments": { "advertiserId": "42" } } ``` To open one seller, pass its exact Storefront id. Add `connectionAction` when the user asked to set up another authorization grant; it opens the relevant detail and leaves the final action to the buyer: ```json theme={null} { "name": "open_connections_page", "arguments": { "sellerId": "84", "connectionAction": "connect" } } ``` Do not invent an id. Resolve advertiser ids from the advertiser catalog or the active conversation scope, and seller ids from `search({kind: "seller"})`. Account-scope responses preserve the empty `{}` result; scoped responses echo only the supplied widget seeds. The response carries the Media Partners page resource (`ui://agentic-api/connections/mcp-app.html`) in `_meta`; a host that renders MCP-UI widgets opens the page. Hosts that don't render widgets receive a plain confirmation and no connection data — the tool never returns connection facts itself. The embedded app uses the same public V3 contract available to agents: `search`/`get` for sellers, connections, and advertisers (provider accounts and mappings are bounded detail on a connection); `save_connection` for connection desired state; and `save_ask` for a supply request. Advertiser setup uses the resource-bound, app-only `open_add_advertiser` handoff. The former app-only bridge remains a temporary rolling-deploy fallback only when the host reports that the public V3 capability is unavailable; service, authorization, and schema errors are shown instead of silently switching protocols. The app never receives the generic `api_call` tool. ## From a headless agent An agent can perform the same workflow without rendering this page: 1. Call `search` with `kind: "seller"` to find the Seller id. 2. Call `save_connection` with that `sellerId` and `authorization`. 3. Open the returned `authorization.url` in an interactive browser, or show the URL to the user when the host is headless. 4. Poll `search` or `get` with `kind: "connection"` until authorization and account discovery complete. 5. Use `save_connection` to refresh/select an account and map it to an advertiser. To enable reporting for exactly one connected account, send `{ "connectionId": "901", "enhancedReporting": { "accountId": "1204", "enabled": true } }`. This is account-scoped and is not a seller feature policy. 6. The same tool can unmap the advertiser or remove the connection if setup needs to be reversed, including while using a signup sandbox. Continue `search` with the returned `nextCursor` until it is absent. The Media Partners widget initially pages the seller, connection, and advertiser collections; it does not fetch every provider account up front. Opening a seller lazily calls `get(kind: "connection")` for that seller's grants and caches the detail by connection id. Connection detail returns provider accounts and advertiser mappings in bounded pages; when `accountsPage.hasMore` or `accountMappingsPage.hasMore` is true, call `get` again with the corresponding `connectionAccountsOffset` or `connectionMappingsOffset`. `save_connection` reports the committed action as successful even if an immediate readback is temporarily unavailable. In that case `object` is null and the response tells the agent to reconcile with `get`; do not retry the write based only on a readback warning. OAuth providers redirect from a one-time Apostra launch. Bearer providers show a focused Apostra form. In both cases the provider credential travels between the browser and Apostra only; it is never returned to the model or MCP host. The launch first shows a **Continue** page, and the one-time capability is consumed only after that button is selected, so link previews and browser prefetching do not invalidate it. ## What the page reads Once open, the page loads live data from the public V3 nouns: * **Media partners** — the Storefront catalog, control plane, and declared capabilities * **Connections** — one summary per authorization grant, joined to its seller by `sellerId` * **Advertisers** — the account's advertisers and preferred reporting time zones, to map accounts against Provider accounts and advertiser mappings load only from the selected connection's bounded detail. The connections projection includes each seller's declared capabilities, which the page uses to gate event and audience controls. Events and Audiences are independent, off-by-default consents written through `update_storefront_connection_policy`, and appear only when the seller declares the corresponding `sync_event_sources` or `sync_audiences` tool. Capability checks load progressively per connection. While a check is pending or unavailable, the page says so instead of treating the capability as unsupported. Connecting a provider hands off to the provider's OAuth; mapping an account to an advertiser is a durable write, and the page surfaces the reason inline if a map or unmap fails so you can retry. See the [connecting ad platforms guide](/v2/guides/connecting-ad-platforms) for the end-to-end flow. An advertiser-scoped seller detail shows each provider account's effective reporting time zone and whether the provider treats it as buyer-selected, seller-assigned, or seller-fixed. If that zone differs from the advertiser's preference, the page shows both and flags the mismatch. Reporting dates remain seller-authored: the provider account's effective zone controls its day boundaries, and mapping does not silently change the advertiser preference. ## Filter by buying readiness, market, or channel The page groups media partners by their current state. **Active** contains only partners whose activation is active for the current account or advertiser. **Needs connection** contains platforms that still require your account connection. **Available** contains the remaining media partners. Buying readiness is separate from activation. The toolbar defaults to **Ready for buying**; choose **All** to include media partners that are not open for buying yet, together with their readiness status. **Needs connection** always keeps its full list so platforms that require your account connection remain discoverable. Buying readiness does not replace activation status: the detail view shows both **Active** and **Not open for buying** when both are true. The toolbar also has **Market** and **Channel** filters alongside the status chips and search box, so you can narrow the list to, for example, every media partner selling in the Netherlands or offering CTV. Options are built from the media partners currently loaded on the page, not a separate lookup: a market appears once at least one loaded media partner's coverage includes it, whether through its declared regions or an approved market-maker grant (Global Market Makers match every market; Regional Market Makers match the markets their grant lists). The filters combine with each other and with the status chips and search box — a media partner must match every active filter to appear — and a **Clear filters** action restores **Ready for buying**, **All markets**, and **All channels**. In the web app, the Media Partners page reads `market` and `channel` from the URL (for example `?market=NL&channel=ctv`), so a shared link opens the page with those filters already applied. Changing a filter afterward updates the toolbar but not the address bar; share a fresh link with the updated `market`/`channel` values to hand someone the same filtered view. Inside Claude, ChatGPT, and other chat hosts, the filters are local to that conversation's view of the page. ## Remove a provider connection **Remove connection** is available in seller detail for an official adapter that has a saved connection. Before anything changes, the page asks you to confirm the organization-wide effect. Confirming archives that connection, revokes and archives its credential, disables the accounts discovered through it, and stops future provider syncs and campaign subscriptions through that grant. Because the grant is shared, this affects every advertiser using the connection. Removing a connection does not erase historical reporting data or advertiser mapping intent. A mapped provider account remains usable when another active grant can reach it; otherwise the mapping is retained but unavailable until the account is reachable again. Any tracked-campaign subscription is stopped as part of the archive. Reconnect the provider to create or restore usable access. Publisher storefronts without an adapter connection record do not show this action; their approval-gated relationship lifecycle is separate.