Current availability audit · 20 Sep 2026 UTC

Current Union Alpha availability: retired preview, unlisted Go alias

Audit window: 2026-09-20T07:32:44Z–2026-09-20T07:35:01Z UTC. This was a narrow route-status and attribution-scope audit. It did not include broad benchmark or rumor search, paid Pareto evaluation, account creation, subscription, purchase, an old-slug request, a load/capacity test, retry, or private-code request.

Decision brief

Current answer

Do not start a new integration on either former Union Alpha identifier. The OpenRouter preview is retired/no longer catalog-listed, and the former OpenCode Go alias is no longer listed in the inspected current Go sources. The paid Pareto route is a separate catalog listing, not a demonstrated fixed Union Alpha replacement. No request was sent (n = 0).

The OpenRouter preview remains retired/no longer current-listed. The historical stealth/union-alpha page says its free stealth period ended, identifies the model as Pareto by Unbiased, and directs readers to paid unbiased/pareto. The current public catalog has Pareto but no stealth/union-alpha entry. This is catalog and historical-page evidence—not an old-ID HTTP request or a claim about any old key. R3-S01 · R3-S02 · R3-S03
The R2-named Go alias is now absent from both current Go documentation and public catalog. The inspected documentation had no Union Alpha/union-alpha text, endpoint row, privacy row, or model row; the public GET /zen/go/v1/models result had no union-alpha ID. R2’s “documentation-only” route becomes no longer listed in inspected current Go sources, not “working,” “entitlement-blocked,” or an observed API error. R3-S06 · R3-S07
No Go request was sent (n = 0). The prerequisites for a tiny Go request both failed: the alias was not currently documented/listed and names-only environment checks found no pre-existing Go credential. There is no request, HTTP result, latency, provider/routing field, rate-limit header, error, DNS event, or availability sample.
Attribution is precise only for the former preview. OpenRouter says Union Alpha was revealed as Pareto by Unbiased; Unbiased describes Pareto as blended and says Unbiased/Pareto are built and maintained by Circuit & Chisel. No inspected source says the former OpenCode Go union-alpha alias was Pareto, identifies its composition, or maps either alias to a fixed Pareto/version snapshot. R3-S01 · R3-S09 · R3-S10
Do not transfer limits, privacy, or performance across routes. The retired preview’s historical retention wording is not current Pareto policy; R2’s Go 0 days/Not used row is no longer in the current Go document; generic OpenRouter free-variant rules remain non-model-specific; page telemetry and provider-published Pareto 26.9 scores are not audit results or Union Alpha snapshot proof. R3-S04 · R3-S06 · R3-S10

Route decision record

Route / identifier	Current source evidence	Direct access evidence	Classification	Safe next action
OpenRouter former preview `stealth/union-alpha`	Historical page says reveal = Pareto by Unbiased and free period ended; live catalog omits the ID.	0 requests; old slug deliberately not requested.	Retired / no longer listed	Do not start a new integration on this ID. Treat its 262K, text/image, and retention statements as historical preview metadata only.
OpenRouter successor `unbiased/pareto`	Current catalog/listing gives paid price, 262K/131,072 declared limits, text+image→text, and `tools`/`tool_choice`; Unbiased describes a blended model.	No request; paid-successor evaluation was excluded.	Current catalog-listed, not access-tested	If separately authorized to evaluate it, first review current route-specific access, price, and data terms. Do not call it the immutable Union Alpha snapshot.
OpenCode Go former alias `union-alpha` / `opencode-go/union-alpha`	R2 had a current listing; current Go docs, endpoint/privacy tables, public models endpoint, and inspected changelog do not name it.	0 requests; no pre-existing authorized credential and no current listing.	No longer listed in inspected current Go sources	Do not use or request the former alias. Monitor official Go sources for an explicit re-listing or mapping.

Classification boundary: public catalog presence would only be catalog evidence, not entitlement or successful inference. Catalog omission does not reveal the HTTP response an old ID would produce. Neither status is a quota, SLA, capacity estimate, or snapshot-equivalence conclusion.

R2 → R3 volatile-claim delta

Field	R2 finding (18 Sep)	R3 finding (20 Sep)	Status / boundary
OpenRouter old listing / ID	Preview ended; public catalog omitted `stealth/union-alpha`.	Same.	Reconfirmed historical/retired state — R3-S01–02; not an old-ID request.
OpenRouter successor / price	`unbiased/pareto` catalog-listed, paid at $2.50/M input, $7.50/M output, $0.25/M cache read.	Same listed price; current catalog canonical slug `unbiased/pareto-20260917`.	Reconfirmed current catalog listing — R3-S02–03. Not a paid test.
Declared context/output/modalities	Old historical page and Pareto showed 262,144 context; Pareto 131,072 max output; text+image→text.	Same declared historical/current metadata.	Metadata only — R3-S01–03. No immutable behavior inference.
Tools / structured output	Pareto listed tools/tool choice but no `response_format`.	Catalog still lists `tools`/`tool_choice` and does not list `response_format`.	Declaration only — R3-S02. No tool test.
Attribution	Former preview revealed as Pareto by Unbiased / Circuit & Chisel.	Same explicit attribution.	Reconfirmed — R3-S01, R3-S09. Components/weights unknown.
Go-alias ↔ Pareto/version mapping	No source proved the relation.	Still no explicit mapping; alias absent from inspected Go sources.	Unverified; gap sharpened — R3-S06–10.
Historical OpenRouter data-use wording	May be retained by provider; not used for training.	Same wording persists on historical page.	Historical-only — R3-S01. Not Pareto/Go policy.
Current Pareto data-use/retention wording	Not established.	Not established in this narrow audit.	Unknown. Do not send sensitive code based on historical wording.
Go alias listing / endpoint	Docs and public models endpoint named `union-alpha`, with endpoint/config format.	Docs/public models result do not name it; no current Union Alpha endpoint/config row.	Changed: no longer listed — R3-S06–07.
Go entitlement / price / limits	`Free (limited time)` and displayed `Unlimited` estimates under $10/mo Go subscription.	No current Union Alpha row; generic Go usage docs cannot be assigned to Union Alpha.	Changed: no current alias-specific entitlement or limit found — R3-S06.
Go alias privacy	`Not used` / `0 days`.	No current Union Alpha privacy row.	Changed: prior route-specific statement is historical; current status unknown — R3-S06.
Generic OpenRouter limits	Free-variant policy did not establish a Union Alpha/Pareto quota.	Same; policy scopes free variants to IDs ending in `:`.	Reconfirmed non-applicability — R3-S04.
Direct Go access	n=0; no authorized credential.	n=0; current listing absent and credential names absent.	No direct observation; blocker changed/compounded.
Capacity / latency / SLA	No direct sample; Pareto page telemetry not runner measurement.	Same.	Unknown — R3-S03.
Benchmark evidence boundary	Pareto 26.9 provider claims/method material were not independent Union Alpha preview results.	No new benchmark work; model card still calls values Pareto 26.9.	Preserved boundary — R3-S10.

Access, limits, privacy, and equivalence — strict boundaries

Former OpenRouter preview

Historical only

Access: retired/no longer catalog-listed; no old-ID request was made. The historic page says the free period ended; do not represent the historic $0 preview as current. Its retained/not-trained wording is not an assurance for a current paid successor. No Union-Alpha-specific quota is established: a historical catalog omission and per_request_limits: null do not mean unlimited.

Current paid Pareto

Separate route

Attribution: directly named by the historical reveal; Unbiased calls it blended/multi-model and Circuit & Chisel builds and maintains it. Its listing does not prove a former Union Alpha call or Go alias used the same components, weights, routing, version, policy, capability, or benchmark snapshot. Do not infer entitlement, retention, quota, SLA, uptime, composition, performance, or private-code safety.

Former OpenCode Go alias

Removed from inspected sources

Current state: absent from the documentation/catalog audit, which is stronger than R2’s documented-but-untested state but does not reveal an HTTP error. Exactly zero Go-alias requests were sent; no account, subscription, or purchase was created. R2’s 0 days/Not used/Unlimited language is dated historical documentation, not current policy or entitlement.

Generic policy is not a route quota: OpenRouter’s free-variant rule is scoped to variant IDs; it does not establish a Union Alpha or Pareto limit. Likewise, per_request_limits: null does not mean unlimited. R3-S04

Evidence and method

The audit used a source ledger, start/end captures, a capture-method note, checksums, and a credential/no-request record. Public claims here link to the primary sources below. The narrow audit’s no-request decision is material evidence: it means the page makes no direct HTTP, latency, route, rate-limit, capacity, or availability claim.

Primary source URLs

OpenRouter historical Union Alpha page (R3-S01)
OpenRouter live catalog (R3-S02)
OpenRouter Pareto (R3-S03)
OpenRouter limits (R3-S04)
OpenCode Go docs and public catalog (R3-S06–07)
Unbiased and Pareto model card (R3-S09–10)

What this changes for use

Former OpenRouter preview: do not use stealth/union-alpha for a new integration. Its historical page indicates ended/no longer catalog-listed status; no old-slug request was sent, so this page makes no HTTP-error claim.
Paid Pareto successor: unbiased/pareto is a separate current route, not a demonstrated immutable preview replacement. Evaluate it only with separately approved budget/access/retention review. Do not send sensitive code until current route-specific data terms are acceptable.
Former OpenCode Go alias: do not configure opencode-go/union-alpha from R2 instructions. If official sources re-list it, a future, separately authorized evaluation should begin with one tiny non-sensitive request and preserve its evidence; one request would still not establish capacity, reliability, quota, SLA, or equivalence.

Open questions

Will OpenCode issue an official announcement or re-list union-alpha, and explicitly map the alias to Pareto or a version snapshot?
Will an official source publish current Pareto route-specific data-use/retention terms, components/weights, or a mapping to the Sep. 16 preview?
If an alias is again current-listed and an authorized credential exists, what does one minimal non-sensitive request show? That observation would be n=1, not a capacity, reliability, quota, SLA, or equivalence result.

See the summary, benchmark boundary, identity evidence, historical user reports, and access guidance. Earlier published records: R2 and R1.