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When your storefront uses a third-party AdCP-compatible sales agent as an inventory source, Interchange can help you answer two different questions:
  • Is the source set up correctly? Check source status, credentials, advertised capabilities, and compliance.
  • What happened on recent buyer traffic? Inspect recent AdCP calls, responses, task statuses, and failures for that source.
Use both. A source can be configured correctly but still fail a specific buyer request, and a failed buyer request can come from a valid business rejection rather than a broken connection. Setup, request eligibility, and health are separate. Interchange sends a discovery request when the Source is set up, not paused, mapped to an eligible Agent, and compatible with that request. Degraded or erroring health remains visible but does not automatically stop requests. A serious health problem may lead an operator to record a separate, reasoned ineligibility decision.

A timeout is not an error response

A typed timeout means the call did not finish inside the observer’s budget. It does not mean the Source returned an error, is unreachable, or is currently unhealthy. For example, a get_products call can exceed a 30-second buyer window and then complete successfully in 35.7 seconds when observed with a longer 45- or 60-second budget. A fresh test with the same 30-second budget may simply reproduce that budget mismatch; compare it with a 60-second observation before diagnosing reachability. The response exposes the mechanism as condition: "timeout", separately from the diagnostic impact (status: "degraded"). A completed error response uses condition: "error_response"; a connection failure uses condition: "transport_error". Reporting has its own health axis, so an inventory observation timeout does not make healthy reporting unhealthy. None of these health observations changes request eligibility by itself. Human-facing Source Health surfaces use one vocabulary: Healthy, Degraded, Erroring, and Unknown. The detailed diagnostics API keeps the older unhealthy value in source.health.status and capability observations for wire compatibility; clients should present that value as Erroring. Do not infer the failure mechanism from that status. Read condition: timeout is observer-budget exhaustion and is degraded evidence, while error_response means the Source actually returned an error. Diagnostics keep three evidence types separate:
  • A source test is an explicit sandbox test against the selected source.
  • A source call is an observed protocol exchange with the selected source, such as get_capabilities or an Agent-supplied get_products request.
  • A storefront buyer-path or composition run describes work at the storefront layer. It is not evidence that the selected source was called unless a source exchange is attached to it.

Physical transport evidence

transportRequests is the bounded, redacted record of outbound protocol attempts. It is separate from logical recentActivity and the health verdict: one logical operation can create several physical requests. For media-buy creates and updates, groupId identifies the application operation and each SDK session keeps its own debugId. Local stages show setup and whether mutation dispatch was attempted. physicalRequestCount excludes local stages; logicalOperationCount counts accepted operation envelopes. If mutation_not_dispatched is present, Interchange stopped locally and no remote mutation request or response was recorded. This does not establish that the remote media buy is unchanged. An authoritative readback is required. This distinction matters for no_ingredients: a composition run can stop at the storefront before it calls the external sales agent. That failure must not be shown as a failed source call or source test. On the Agent-supplied product path, the storefront sends the brief to the external agent’s get_products; that call uses the agent’s finished products and does not require ingredients.

Read seller readiness without combining unrelated results

For a source linked to an Agent, Source Diagnostics shows three separate results:
  • Marketplace availability says whether the storefront can currently transact. Resolve any listed blocker in Seller Setup.
  • Agent certification applies to the Agent’s current revision. If it needs attention, open the Agent page and complete its certification work. A stale certification does not by itself change the marketplace result shown here.
  • Source health is the latest observed condition for this exact source. When it is degraded, erroring, or unknown, open Setup and refresh capabilities before changing the source. That refresh checks the endpoint, credentials, and declarations; it does not prove product discovery or a media-buy lifecycle.
Use validation when you need new no-spend evidence for the exact source. A successful source check is not a replacement for the storefront’s own availability decision or for current Agent certification. If the source has no organization-owned Sales Agent, Source Diagnostics offers the Create Agent Task for a self-operated replacement and a Scope3 support route for a Partner connection. A revoked Partner mapping cannot be restored from this page: Scope3 coordinates that cross-organization connection. For external sales-agent sources, also separate live source health from component-cache health. Live health answers whether Agent-supplied discovery or media-buy calls reached the source and completed. Component-cache health answers whether Interchange can read the source’s raw products/components for merchandising without calling the source during buyer-request composition. Cache complaints usually mean the source does not support a usable component response, returned invalid/missing product metadata, has an errored or cold cache state, or cannot refresh because of auth or reachability. Stale-but-usable cached rows are not automatically a failure; they are valid composition inputs when the storefront allows hard-stale OK cache reads. Soft-refresh age is handled automatically by Interchange’s stale-while-revalidate cache path; it does not create a seller action item. A cache complaint does not by itself mean live the Agent-supplied product path is down. Interchange does not make wholesale product or signal catalog requests to every external sales agent. They run only when the Source’s explicit product contract includes the Storefront-built path and the Agent reports AdCP 3.1+ support. An Agent-supplied Source focuses on live buyer-request activity instead of component-cache readiness. Only wholesale products are composition inputs; ordinary finished products are not reclassified as ingredients. Managed ad-server Sources have a fixed wholesale contract because their raw inventory must be turned into products. Neither product path is separately monetized. When a seller-operated source stays unhealthy long enough to trigger a proactive Murph alert, the alert links directly to this diagnostics surface with the affected source selected. Open that link first, then use the recent activity and developer handoff sections for the partner-safe debug ID, task ID, operation ID, and correlation headers behind the failing calls.

Endpoint

GET /api/v2/storefront/inventory-sources/{sourceId}/diagnostics Returns seller-facing diagnostics for one third-party sales-agent or modular inventory source. The response combines the current source setup, recent AdCP activity, test-run evidence, latency rollups, error rates, discovery participation, demand impact, and developer handoff identifiers. New outbound calls include a partner-safe x-scope3-debug-id that also appears in the diagnostics handoff.

Canonical reporting evidence

The response’s reporting field is an independent projection of the canonical reporting ledger for this exact Source. It does not derive reporting health from generic Source activity or copy one Source’s result onto its Agent.
  • availability says whether canonical reporting evidence is supported or unsupported. It is null when no value was observed.
  • health uses waiting, healthy, delayed, action_required, and complete.
  • sourceProvenance: acquired appears only when an immutable acquisition plan proves the Source attribution. null means that proof was not observed, not that the Agent lacks reporting capability.
  • obligations preserves period, expected time, required finality, coverage, missing-first-report state, issue ownership, and latest revision evidence.
  • lastSuccessfulRevision, dataThrough, nextExpectedAt, and freshness describe the most recent usable reporting state.
  • Truncation flags mark bounded obligation and related-media-buy collections. A response that exceeds the obligation-row limit returns nullable aggregate reporting state instead of projecting health from partial evidence.
A reporting-ledger read failure does not erase otherwise-valid Source diagnostics or change inventory health. In that case reporting returns a nullable projection. The action descriptors are read-only integration seams and remain unavailable with reason: adapter_pending until their typed adapters are connected. To run a direct source test, use the shared storefront operation run_inventory_source_discovery_test, backed by: POST /api/v2/storefront/inventory-sources/{sourceId}/tests/discovery This source-scoped operation calls the selected external sales agent’s get_products with a read-only brief. It creates no media buy, spends nothing, and does not test reporting or webhooks. Its outcome, product count, step, and available debug identifiers are recorded as a durable source test run, so the result remains available from list_agent_test_runs and in Source Diagnostics.

Refresh current health evidence

If Source Diagnostics shows stale or conflicting health evidence, ask Murph to refresh the affected inventory source, or call refresh_inventory_source_health from an MCP client with that source’s sourceId. No refresh is needed when diagnostics does not request verification. The operation sends one no-spend get_products request to that source. It does not change source configuration, create a media buy, or test reporting or webhooks. Its response returns the timestamped outcome, recorded run, task, operation, debug, and correlation IDs, and refreshed storefront readiness. The same evidence appears in Source Diagnostics. MCP hosts open the same Source Diagnostics app through the typed open_source_diagnostics tool. The widget and its actions use shared MCP contracts rather than sending a new chat message to Murph.

Run the full Sales Agent validation

For a third-party Sales Agent Source, Test & certify runs the current test-sales-agent skill. A separate Buyer Account is optional: when you do not select one, Interchange creates the validation Advertiser and draft Campaign inside the Media Company account’s isolated seller sandbox. If you do select a reachable Buyer Account, validation continues to use that account. Choosing No auth completes credential setup for a public endpoint; there is no secret to submit. Murph inspects the saved Source and continues to diagnostics instead of reopening the credential form. A validation window with no qualifying calls remains untested, not failed.

Request

Parameters

Response

The most important response blocks are: diagnosis.owner tells you who must act:
  • seller — a generic external sales agent you operate, or an adapter whose credentials need re-authorizing. The topCause and nextSteps are addressed to you.
  • scope3 — an official Scope3-hosted adapter (Pinterest, Reddit, Snap, …) whose runtime is failing. Scope3 operates that runtime; the failure is ours to fix and recovers automatically, so there is nothing for you to do. nextSteps will say so rather than asking you to debug our infrastructure.
diagnosis.topCause is the primary explanation to show first. Use diagnosis.issues[] when more than one signal is present in the same window: for example stale async callbacks, caller-deadline timeouts, slow responses, non-timeout failures, input-required responses, business rejections, skipped diagnostic attempts, missing auth, or inactive sources. Each issue includes a stable mode, severity, affected count, and human-readable summary. Issue mode values use the same source failure vocabulary as the diagnosis model, such as stale_async, timeout_degraded, auth_missing, source_runtime_error, business_rejected, and input_required. comparison.trend is a quick movement signal, not an uptime or SLA claim. It compares sampled source activity in the requested window with the immediately previous window of the same length. not_enough_data means neither window has enough source activity to compare; latency remains unknown when request and response rows cannot be paired. Zero calls in the selected window means the operations are untested in that window. It is not a failed call and cannot, by itself, support an Erroring verdict. Likewise, missing validation assertions mean no qualifying run has assessed them yet; read the captured health observation or failed exchange before attributing a failure to the Source. The latest source-health check can be older than the selected activity window. When an older failed check has no newer traffic to confirm or clear it, the overview labels it as stale evidence and asks for current verification. It does not claim the source is currently down, and it does not say that no action is needed. A healthy completed get_products result takes precedence over an unhealthy sync_creatives observation only when it is at least 24 hours newer and both observations remain inside the seven-day freshness window. Other current unhealthy observations stay visible and can still affect readiness.

Capability health observations

source.health is one collapsed cell for the inventory axis: the same worst-of-fresh collapse described below for capabilityHealth.inventory, not whichever check happened to write last. Its own status field is healthy, degraded, unhealthy, or unknown (unknown when nothing has ever reported) — a survivor of the per-source column this field has always read, kept as its own four-value field for compatibility. Present unhealthy as Erroring in human-facing output. Two of its other fields follow the same “worst check wins, not last check wins” rule, which matters when more than one check is reporting on the same source:
  • lastSuccessAt is the last time the currently worst-reporting check saw a healthy result, not the most recent success across every check. If that worst-reporting check has never once succeeded, lastSuccessAt reads null even though a different, healthy check has a success history.
  • lastErrorAt clears back to null as soon as the collapsed status is healthy, rather than continuing to show a past error that no longer reflects current state.
source.capabilityHealth is the fuller picture behind that cell, and it uses a different convention for “nothing has reported”: null instead of the string unknown. It has two axes, inventory and reporting, and each axis carries both a derived status and the observations[] evidence behind it: Each entry in observations[] has: Three things follow from that shape:
  • Different checks watch the same source and can disagree. A source can have one check confirming get_products connectivity while a separate reporting check is failing, and both readings stay visible in observations[] at once: for example, one check reporting the connection is fine while another reports the reporting feed failing. The old single cell was last-writer-wins: whichever check happened to run most recently silently overwrote whatever the others had reported, and the disagreement was lost. status restores that visibility without giving up a single verdict: it is computed across every reporting check, not just whichever wrote last.
  • An empty observations array means no check has reported on that axis yet, and status reads null accordingly. A source with no reporting checks configured shows "reporting": { "status": null, "observations": [] }; read that as “not observed,” not as “reporting is fine.”
  • A reading can go stale, and status already accounts for that. A check that stopped running leaves its last reading in place indefinitely; status discounts a reading old enough to no longer describe current state in favor of fresher evidence on the same axis. The same rule this page already applies to source.health applies here: a failure with no newer activity to confirm or clear it is stale evidence that needs current verification, not a confirmed current outage.
  • Each axis’s observations[] array is capped at 20 readings, newest first. A source realistically reports through a handful of named checks per axis, so this is not a limit you should expect to hit in practice.

Errors

  • 400 BAD_REQUESTwindowHours is not a positive integer or is greater than 720.
  • 401 UNAUTHORIZED — missing or invalid API key.
  • 404 NOT_FOUND — no inventory source with this sourceId exists for the storefront.
See Errors for the full error contract.

Open the diagnostics surface

Source diagnostics overview showing a sales-agent source that needs attention, error counts, late callbacks, and the next investigation action
Diagnostics open from the source you are looking at, scoped to that source:
  • From the source itself. In the ad-server or sales-agent source app in chat, use Open full diagnostics. It opens the Source Diagnostics app already focused on the connection you had selected. (The in-app View details / View diagnostics buttons are different — they switch to the advanced tab inside the same source app.)
  • From Pending operations. When a source you operate degrades, it appears in the Sources degraded group of the Pending operations view with its severity and a one-line summary. Each row’s Open full diagnostics opens the Source Diagnostics app scoped to that source.
  • By asking Murph. Ask “why is <source> failing?” or “show me diagnostics for <source>” — Murph opens the Source Diagnostics app scoped to that source. Naming the source focuses the app on it; otherwise it opens on the source you last had selected.
  • From the Help menu. Open Ask Murph, choose Help, then choose Diagnostics for the storefront-wide diagnostics view (change history, Calls, source tools, test runs).
Choose Show me from a Source Diagnostics announcement, or choose ? in the diagnostics surface, to start the two-minute quick tour. The tour teaches the same operating sequence in every supported chat host:
  1. Start with the question: is this source healthy, what changed, and who acts?
  2. Choose the evidence window. Start with 24 hours, narrow for an active incident, or widen it to confirm a pattern.
  3. Read the overview verdict before inspecting individual calls.
  4. Use Evidence for recent calls and partner-safe handoff identifiers.
  5. Take the smallest diagnosed next action, then refresh or run a focused test.
The surface has three primary views: Summary, Evidence, and Setup. Run discovery test calls the selected external source’s get_products directly with a read-only, no-spend brief and records the result as a durable source test run. It does not create a media buy. Refresh capabilities is the secondary setup check: it calls the source capability endpoint directly and shows the result in the app; it does not send a synthetic question to Murph. Capability refresh verifies endpoint reachability, credentials, and declared tools only—it does not prove discovery. The refresh is scoped to the selected Source’s own connection identity, so it works even when that Source has no legacy standalone Agent record. A buyer-path result appears under the selected source only when diagnostics have an observed source exchange to attribute to it. A storefront intelligence run that stopped before source dispatch remains storefront evidence, not a failed call against the external agent. In Setup, diagnostics show the selected Source’s provider-declared mode, effective product path, and readiness. That authority is read-only in Interchange. To remediate an incomplete wholesale path, correct the Agent’s reported product, property, format, pricing, or execution declaration, then ask Scope3 support to refresh or reconcile the capability. Do not change a mode to hide a readiness failure. For an Agent-supplied source, Connected means its source connection and required credentials are ready. Setup does not wait for an Interchange wholesale catalog, and a null reporting status (no reporting check has reported yet) does not become setup work. A subsequently observed degraded or unhealthy source is shown as Needs attention instead.

Powered by

When the selected Source is backed by a Sales Agent, Setup shows a Powered by card naming that Agent and linking to its Agent Page. The card’s heading reflects who holds the Agent, not just that one exists: See Agents for the underlying powered-by-agent endpoint and its ACTIVE / UNMAPPED / REVOKED states. The tour changes tabs and highlights controls, but it does not change source configuration. Any product action keeps its normal safeguards. You can also open Source Diagnostics directly by replacing <account-id> with your account id:
To focus the app on one inventory source, include diagnosticsSourceId:
Task-level filtering is available inside the app’s recent-call search after it loads; there is not currently a task-id deep link. Slack cannot render the MCP app inline. When Murph diagnoses a sales-agent source from Slack, it provides this same account- and source-scoped link as a Open sales-agent diagnostics button. Open it, choose Run discovery test, then reply done in the Slack thread. Murph looks up the recorded source test and interprets it; you do not need to copy the result between apps.

Start with the inventory source

Open the storefront inventory source in the app, or call Get storefront readiness. The sourceDiagnostics[] entry for each source gives the current operating picture: If the source is not active, credentials are missing, or the source does not advertise the tool you need, fix that before debugging individual buyer requests. Treat a failed capability refresh and failed source traffic as separate signals. A refresh can fail while a recent get_products call succeeds, and that successful call is direct evidence that the source responded. Planning can continue from a clearly labeled last-known capability document; when no capability document is available, it reports the probe failure separately instead of treating missing metadata as proof that the source is unreachable.

Understand product paths

The productMode.paths[] diagnostics report each Source’s effective runtime path and its readiness. Storefront-built means Interchange can use ready wholesale inputs from the Source when composing products. Agent-supplied means the connected Agent returns complete buyer-ready products. An Agent that supports both reports each path independently; a problem on one path does not silently reclassify the other. Use the Source’s normal detail page for connection and operating actions, and use productMode diagnostics to identify whether the Source, Scope3, or the connected Agent owns a readiness problem. Storefront readiness also includes Interpretable product formats when canonical-format compliance is enabled for your storefront. Direct canonical format_options[] and projectable legacy {agent_url, id} references both pass, regardless of source age. If a legacy product contains several format references, at least one usable canonical projection keeps the product available; an unsupported sibling reference is omitted from the buyer-facing format options and remains visible as an advisory diagnostic. A product with no usable canonical option is withheld on its own, while the Source and its other products remain request-eligible. Seller Setup prefers public catalog evidence when a source has it, so an older buyer-account or sandbox-test observation does not override a corrected public declaration. Buyer discovery and purchase still validate the relevant account context before products can serve. The readiness check names unresolved products and their affected Source as repair guidance; it does not make the storefront transaction-ineligible. Replace an unsupported custom reference with an exact shared-catalog reference or publish an interpretable custom canonical declaration. The Source’s separate connectivity health can remain healthy because a successful response with a partial catalog warning is not a reachability failure. This compatibility policy is distinct from observed Source health. A health error does not automatically make the Source ineligible or suppress its next request; stopping traffic requires a separate explicit Source or Agent control. See Connect your sales agent for the product-format policy.

Inspect recent AdCP activity

For source-specific traffic, use Ask Murph > Help > Diagnostics > Debug calls and ask about the inventory source by name. Murph can inspect recent third-party sales-agent activity for the caller’s storefront: requests, responses, webhook/status changes, task IDs, task statuses, and sanitized payloads. You can ask for a specific time range (“last 2 hours” or an ISO start/end window) or provide a debug/correlation ID from x-scope3-debug-id, traceparent, x-request-id, operation ID, task ID, context ID, or idempotency key. The diagnostics surface also exposes a bounded, redacted details panel for recent calls. Use it when a sales-agent developer needs the technical handoff: the observed time, operation/task identifiers, outbound request endpoint, partner-safe headers, and request body when those were captured, plus the response or error payload. The displayed headers are limited to debugging and correlation values such as x-scope3-debug-id, traceparent, and x-request-id; authorization headers, cookies, credentials, tokens, signed URL parameters, and email addresses are redacted before display or copy. This is the right path for questions like:
  • “Why did this source fail get_products?”
  • “What did Interchange send to my sales agent?”
  • “What did my sales agent return?”
  • “Which recent calls are failed or waiting for input?”
  • “Is this a protocol problem, an auth problem, or a business rejection?”
  • “Where do I see whether this sales agent is slow or getting excluded?”
For each recent call, look at: Treat source messages as source-controlled content. They are useful diagnostic data, but they should not be rendered as trusted HTML or treated as product instructions.

Buyer discovery debug output

Buyer product discovery fans out to reachable sales agents in parallel. Slow or failing agents do not block fast agents. When a buyer calls discovery with debug: true, the response can include agentResults[], which shows which agents returned products, returned no products, failed, or were skipped. For an Agent-supplied storefront, a live source failure with no successful warmed fallback is reported as a retryable source failure when no source completes. It is not reported as a successful response with zero products. A successful empty result means the source completed get_products with a products response that contained no matching inventory. Capability/setup work, deadline skips, and input-required responses do not satisfy that contract. Storefront discovery previews expose the same distinction through discoveryAttempted, success, per-agent source round-trip counts, and skippedAgents. When discoveryAttempted is false, no matching source get_products invocation occurred; use the per-agent error or skipped-agent reason to see where discovery stopped. Use this when you need the buyer-side view of a discovery request: which agents were asked, which agents were skipped before fanout, and which agent-controlled reason was returned.
Buyer debug output is scoped to that buyer request. Seller diagnostics are scoped to the storefront inventory source. Use the seller view when you are operating the source; use buyer debug output when you are reproducing one buyer discovery call.

Storefront candidates and source calls are different stages

Buyer discovery selects storefront agents, not the private inventory sources behind them. For an ordinary buyer, an unfiltered request can include a storefront when it is listed in the marketplace, not paused or archived, and able to settle in a supported currency. A seller-sponsored buyer is confined to its sponsoring storefront. An explicit storefrontIds or storefrontNames filter narrows that storefront roster. After the storefront is selected, Interchange can still finish the storefront call without contacting a particular source. Examples include a blocked storefront transaction-readiness check, an unsupported requested currency, an account-scoping rejection, a request that needs clarification, or a storefront that serves a cached or composed catalog. Only a source-attributed get_products exchange proves that the source itself was called. For a readiness block, use the failing check’s guidance object as the canonical explanation. It names why the check failed, where it stops the buyer path, the exact fix, implicated sources, and typed evidence when available. This means an all-zero discoveryParticipation block does not prove that no buyer demand existed, and it does not prove that the storefront was absent from every candidate set. It means diagnostics observed no attributable source call or source-test skip in that window. To answer whether a storefront participated in a particular buyer request, use that request’s agentResults[] with debug: true. If the original buyer request is unavailable, Scope3 support can correlate the storefront’s buyer-path records with source activity. Two setup fields are commonly misread as routing gates:
  • Empty storefront-card regions or channels do not by themselves remove a storefront from get_products fanout. Requested-channel prefiltering uses the agent’s advertised channel capabilities; unknown coverage remains eligible. Country constraints are passed in the brief for the storefront or source to evaluate.
  • linkedStorefront on an inventory-source response is retained for response compatibility and is always null. It does not attach an AGENT source to its owning storefront and is not a discovery-routing requirement.

Empty responses and latency do not change future ranking

returnedNoProductsCount and latencyStatus are diagnostic observations. They are not inputs to later storefront eligibility, source selection, or product and proposal ranking. There is no rolling empty-response or slow-response penalty window. A source that returns no products contributes no candidates to that individual response, so there is nothing from that source to rank for that request. When a buyer explicitly enables managed screening and ranking, Interchange evaluates the products and proposals returned for the current request against the buyer’s instructions. Without that requested ranking, Interchange does not apply a historical-performance ranking system.

How source latency is measured

The latency fields and a source-test run’s durationMs measure different intervals:
  • Each diagnostics latency sample is one attributable get_products exchange, measured from its recorded request activity to its final recorded response activity. p50LatencyMs, p95LatencyMs, and p99LatencyMs are percentiles across those paired samples in the selected window.
  • latencyStatus is over_threshold when any paired exchange is greater than latencyThresholdMs, or when the window contains a timeout. It is not a comparison between the window’s p95 and the threshold. When no recorded exchange supplies an explicit timeout or deadline, the current diagnostic default is 5,000 ms.
  • A direct source test’s durationMs is wall-clock time for the complete test probe, from source-client setup through completion or failure of get_products. It can include connection/session setup, capability negotiation performed by the client, the get_products exchange, and asynchronous-task handling. It is calculated before trace lookup and test-run persistence. Separate capability calls do not enter the get_products latency percentile, even though they can increase the test’s total duration.
Use the source exchange and transport timeline to split seller-handler time from Interchange/client overhead. Do not compare the run’s total durationMs directly with latencyThresholdMs.

What this does not answer yet

The diagnostics show source state, recent protocol activity, latency percentiles, timeout counts, and source-level skipped/excluded evidence for the selected lookback window. For broader business impact analysis, combine:
  • sourceDiagnostics[].health for the latest known source health.
  • Murph diagnostics for recent ADCP call details.
  • Buyer discovery agentResults[] with debug: true for one discovery request.
If a seller asks for missed product opportunities, lost buyer demand, revenue impact, or longer-term trends, treat that as a product/documentation gap unless a tool returns that exact rollup. The actionable answer should explain what exists today, link to the UI surface above, and call out the missing diagnostic that should be added.

Empty catalog from a version mismatch (VERSION_UNSUPPORTED)

If a source’s products vanish from your catalog and its recent Calls show a VERSION_UNSUPPORTED payload — e.g. AdCP version '3.1' is not supported. Supported: ['3.0', ...] — the source’s AdCP server is rejecting the protocol version Interchange pins instead of serving a compatible one. This is almost always a source-side issue, not a problem with your storefront. Per the AdCP spec, a source that supports the same major version must downshift to its highest supported release and serve the request; VERSION_UNSUPPORTED is reserved for a genuine cross-major mismatch. A source that returns it for a same-major minor (it supports 3.0 but rejects 3.1) is running a non-conformant or stale AdCP server build. At the current 3.1 pin, Interchange does not retry component warming at 3.0 and does not reinterpret a 3.0 response as a component catalog. A one-shot retry hook can become active only for a future pin above 3.1 when the source advertises a compatible same-major GA release that is still at least 3.1. A 3.0-only source may still answer live buyer briefs through the pass-through path, but its components stay absent until the source operator upgrades the server. Share the source name and the sanitized VERSION_UNSUPPORTED payload (from the Calls tab, Details panel) with the sales-agent operator, and point them at AdCP versioning & negotiation for the rule their server must follow.

Practical checklist

When a source is not showing up or a buyer request did not return products:
  1. Confirm the inventory source is active.
  2. Confirm credentials are configured if the source requires auth.
  3. Confirm the source advertises the needed capability, especially get_products for product discovery.
  4. Check source health for the latest error, success, and check timestamps.
  5. Ask Murph to inspect recent Calls for that source.
  6. If reproducing a buyer discovery request, run discovery with debug: true and inspect agentResults[].
  7. If the failure is still unclear, share the source name, task ID, timestamp, and sanitized error with your sales-agent operator or Scope3 support.

Inventory sources

Register and manage the sources behind your storefront

Get storefront readiness

Inspect readiness and per-source diagnostics

Product discovery

Understand buyer discovery and agentResults

Errors

Shared Interchange error contract

AdCP versioning & negotiation

Why a version mismatch empties a catalog, and the downshift rule