[Bug]: Codex Business workspace credit exhaustion shows as a generic runtime error, not a usage-limit stop #9234

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/server

Steps to reproduce

1. Sign Codex in with a ChatGPT Business workspace account (Team/Enterprise behave the same) whose credits are exhausted.
2. Send any message in a Codex thread.

Expected behavior

The same treatment a Plus/Pro usage limit gets: the thread says Codex is out of quota, who can fix it, and stays visibly parked as a limit rather than a failure. Once #9012 lands, plan limits show a labeled "Usage limit reached — limits reset …" notice; the Business equivalent is "Workspace is out of credits — ask your workspace owner to add credits", with no countdown (credits are refilled, not reset) and cleared the next time Codex reports credits.hasCredits: true.

Actual behavior

A generic red thread error banner carrying Codex's raw sentence. It is indistinguishable from a provider crash, so it reads as "something broke" rather than "you hit a limit", and there is nothing telling me the thread is waiting on the workspace owner.

Why, verified against source:

• Codex classifies all four workspace stops — workspace_owner_credits_depleted, workspace_member_credits_depleted, workspace_owner_usage_limit_reached (spend cap), workspace_member_usage_limit_reached — as CodexErrorInfo::UsageLimitExceeded, the same error code as Plus/Pro limits (codex-rs/protocol/src/error.rs, to_codex_protocol_error). Only the message text differs.
• Codex's account/rateLimits/updated snapshot carries the structured facts: rateLimitReachedType, planType (business, enterprise, team, …), credits { hasCredits, balance, unlimited }, spendControlReached.
• CodexAdapter only treats the account as limited when a rate-limit window is at 100% and has a resetsAt. Credit depletion has neither, so the structured signal is dropped on the floor.
• The failed turn/completed then stamps the message into session.lastError (ProviderRuntimeIngestion.ts), which every client renders as the generic red ThreadErrorBanner.

This is the Business-account sibling of #6513 (Claude) and of the plan-limit handling in #7165 / #9012. Business plan types were already a blind spot once (#8537, #8292).

Impact

Minor bug or occasional failure

Version or commit

main@70cd258d8 (also reproduced on the #7165 and #9012 branches)

Environment

Linux (Arch), web client against a local t3 server. Codex CLI signed in with a ChatGPT Business workspace account (credit-based billing).

Logs or stack traces

Shape of the exchange per the app-server protocol (schema, not a captured log):

error            { error: { message: "Your workspace is out of credits. Ask your workspace owner to refill in order to continue.",
                            codexErrorInfo: "usageLimitExceeded" }, willRetry: false }
turn/completed   { turn: { status: "failed", error: { message: "Your workspace is out of credits. …" } } }
account/rateLimits/updated { rateLimits: { planType: "business", rateLimitReachedType: "workspace_member_credits_depleted",
                            credits: { hasCredits: false, … } } }

Screenshots, recordings, or supporting files

Workaround

None inside T3 Code. The workspace owner adds credits, then the user starts a new turn.