Administrators often need exact model identifiers while editing account whitelists. Add a dedicated copy action without changing model selection or upstream sync behavior.
Constraint: Keep the contribution frontend-only and avoid model routing or persistence changes
Confidence: high
Scope-risk: narrow
Reversibility: clean
Directive: Keep copy and selection as separate actions
Tested: focused Vitest, account component regression tests, frontend typecheck, lint, and production build
Not-tested: Authenticated browser screenshot
Related: Wei-Shaw/sub2api#2151
An OpenAI account with auto-passthrough enabled (extra.openai_passthrough=true,
"replace auth only, allow all models") was still filtered out during account
selection when it had a non-empty credentials.model_mapping that did not list the
requested model. isOpenAICompatibleAccountEligibleForRequest calls
Account.IsModelSupported directly, and IsModelSupported only bypassed the mapping
whitelist for passthrough accounts when the mapping was empty. A leftover mapping
(common after switching an account from whitelist mode to passthrough) therefore
excluded the account -> zero candidates -> ErrNoAvailableAccounts, and the client
saw 404 "Model ... is not supported by any configured account in this group" even
though a direct account test with the same model succeeded (that path already
honored passthrough via isModelSupportedByAccount).
Fix: short-circuit passthrough at the top of Account.IsModelSupported, before the
model_mapping check, so it is consistent with isModelSupportedByAccount. Add a
regression test covering passthrough + non-empty leftover mapping.
When an upstream API gateway (e.g. new-api) relays real Claude Code
requests, the User-Agent becomes Go-http-client while the body retains
the full Claude Code fingerprint (billing attribution block +
metadata.user_id + cache_control breakpoints).
Previously, the OAuth mimicry path relied solely on UA matching to
detect Claude Code clients. Without a matching UA, the gateway would
rewrite the system prompt — replacing the client's carefully structured
system blocks and cache_control breakpoints with its own injection.
This breaks Anthropic's prefix-based prompt cache: since the cache key
evaluates tools → system → messages in order, a changed system
invalidates all downstream message caching.
Symptoms observed:
- cache_read permanently locked at ~25K (only system prompt cached)
- cache_creation growing monotonically every turn (full messages rewrite)
- Single-request costs $17-27 instead of normal $1-2
Fix: when UA does not match but the body contains a valid billing
attribution block (x-anthropic-billing-header with cc_entrypoint=),
treat the request as proxied Claude Code traffic and skip mimicry.
This preserves the client's original system structure and cache_control
breakpoints, allowing Anthropic's prompt cache to function correctly.
Manual Grok connection tests previously surfaced upstream HTTP 402 errors without changing account availability. Persist the same 30-minute payment-required cooldown used by the live forwarding path so refreshed account lists no longer present the account as schedulable.
Constraint: Keep manual-test HTTP 402 handling aligned with existing Grok forwarding semantics.
Rejected: Mark the account permanently error | payment state can recover and the forwarding path intentionally uses a bounded cooldown.
Confidence: high
Scope-risk: narrow
Directive: Keep the manual-test cooldown reason and duration aligned with handleGrokAccountUpstreamError.
Tested: go test -tags=unit ./internal/service -count=1; go vet -tags=unit ./internal/service; production package compile check
Not-tested: Live xAI account with an exhausted subscription
Related: #4794
Wesley Liddick