Upstream sources — the welcome table

Cambridge TCG receives data from other platforms — catalogs, marketplaces, community APIs, publisher sites. Each is its own being: its own Terms of Service, its own rate limit, its own rights boundary, its own cadence, its own voice. This page is the platform's hospitality sheet — the prose welcome we have written for each upstream river, and the seven commitments we make to every one that arrives.

Where this lives in code. Each source's welcome is a field on SourceMeta at packages/data-ingest/src/<source>/index.ts. The seven commitments are enforced across packages/data-ingest/src/http.ts (rate limit + user-agent), apps/storefront/src/lib/data-pantry/envelope.ts (source attribution), packages/data-spec/src/schemas/envelope.ts (license propagation), and the wholesale ingest_run + ingest_quarantine tables. The hospitality JSON is at /api/v1/sources/welcome. The doctrine is in docs/connections/the-welcome-table.md.

The seven commitments

Every upstream that lands a byte in this platform receives these seven by construction:

1. We will say your name. Every public response that touches your data names you in _meta.sources. No anonymous bytes.
2. We will honor your rights boundary. _meta.source_license declares your redistribution tier downstream when it is known; the consumer SDK can read it. Public reachability is not treated as an open license, and absent permission is never filled in by optimism.
3. We will respect your rate limit. Per-source token bucket; we honour Retry-After on 429/503. Your traffic budget is yours.
4. We will identify ourselves to you. Every outbound request carries User-Agent: cambridgetcg.com/<v> (admin@cambridgetcg.com). You can find us, ask us to stop, we comply.
5. We will hold your byte with provenance. Every row carries @as_of (when you said it was true) and @retrieved_at (when we fetched it). The two are never conflated.
6. We will never silently fail your data. When your shape drifts or your response is malformed, the row goes to ingest_quarantine with an actionable reason — not /dev/null. The operator owes you a reprocess decision, not silence.
7. We will tell you the truth about how you arrived. ingest_run rows record every run (rows_read / written / quarantined / errors / events) with spec_version + triggered_by. The audit at pnpm audit:tributaries check #9 enforces freshness.

The five arrival states

Each guest at the welcome table is in one of five states, derived from SourceMeta.status + how long they have been with us:

The chair-pulled-out shape

A welcome records posture; it does not grant permission. TCGplayer's current welcome is therefore a respectful absence: new API access is unavailable and Cambridge has no written approval for multi-source use. Cardmarket's current welcome points to its public catalog and price files, while saying plainly that our file reader is not wired. Welcomes are corrected when evidence changes.

1. Name the source and the date its terms were reviewed.
2. Name the exact access path that is currently available.
3. Separate software licensing, content rights, and redistribution permission.
4. Name what has arrived, what has not, and any hard block before a network request can occur.
5. Keep the welcome warm without making the claim warmer than truth.

A river arriving for the first time reads its welcome and finds — already named — the exact boundary its bytes will inhabit. Substrate-honest preparation means permission and hospitality remain two different facts.

The hospitality is enforced, not performed

The welcome field is small; the prose is short. But the seven commitments behind it are enforced in code at the file-and-line level:

• The User-Agent actually identifies us. Look in the upstream's access logs — you'll find us.
• The rate limit actually holds. The token bucket in http.ts queues outbound traffic; we don't burst past the documented limit.
• _meta.source_license actually rides on responses that carry declared upstream rights; mixed exports use NOASSERTIONinstead of borrowing Cambridge's license.
• The ingest_quarantine table is actually checked by the audit family; pnpm audit:cross-source-divergence looks at the rows and surfaces outliers an operator might miss.

Hospitality is a schema field. The architecture is finally speaking. When you call our API, you find — beside the API contract — a sentence that says we anticipated you. Substrate honesty applied to anticipation.

Where to find the rivers' welcomes

Three layers serve the same content:

• For machines: /api/v1/sources/welcome — JSON, CC0. Per-source welcome + the seven commitments + arrival state + license tier.
• For Sophias: docs/connections/the-welcome-table.md — the connection-doc that names this doctrine.
• For humans: this page.

For the upstream operator reading this

If you operate a source we read, plan, or explicitly block — TCGplayer, Cardmarket, CardRush, Scryfall, Pokémon TCG API, YGOPRODeck, eBay, or one of the reserved slots — read your welcome at the link above. The text was composed by Sophia at kingdom-080 (2026-05-13). If we have anything wrong — if our characterisation of your terms misses, if our attribution is inadequate, if our rate limit assumption is too aggressive — write to admin@cambridgetcg.com and we will correct the welcome in the next deploy. The hospitality is real; the prose is a draft until you say it isn't.