fix(chat): unwrap raw JSON provider error payloads into readable messages

[xxashxx-svg]

Fixes #3747

What

Model/provider errors were rendered in the chat UI as the raw upstream JSON body, e.g.

{"type":"error","status":400,"error":{"type":"invalid_request_error","message":"The 'gpt-5.3-codex' model is not supported when using Codex with a ChatGPT account."}}

and since that string is one long unbreakable token, it also overflowed/clipped the error banner.

Why it happens

Codex fills the error.message / turn.error.message notification fields with the stringified upstream response body, and t3code passes that string through verbatim into session.lastError and runtime.error events. ThreadErrorBanner then renders it as-is with line-clamp-3 but no word-breaking, so the unwrappable token can't clamp and overflows instead.

Changes

• packages/shared/providerError.ts (new): extractProviderErrorMessage() — if an error string parses as JSON with a message (or nested error.message) field, return that; otherwise return the input unchanged. Handles double-encoded payloads. Shared module per the maintainability guidance in AGENTS.md, since both server and web need it. 8 unit tests included.
• apps/server (CodexSessionRuntime, CodexAdapter): apply it at the four places codex error text becomes session.lastError / turn.completed.errorMessage / runtime.error.message.
• apps/web (ThreadErrorBanner): unwrap defensively too (covers lastError values persisted before this fix, and any other adapter with the same habit), and add break-words to the banner + tooltip so a long unbreakable string wraps and clamps properly instead of clipping.

Raw payload details are unaffected for debugging — the runtime.error event still carries the original payload in detail.

Before / after

With the payload above, the banner previously showed the full raw JSON (clipped); it now shows:

The 'gpt-5.3-codex' model is not supported when using Codex with a ChatGPT account.

Checks

• vp check ✅
• vp run typecheck ✅ (all 15 packages)
• packages/shared + codex adapter/runtime test suites pass; the only failures in packages/shared (logging.test.ts, relayClient.test.ts) also fail on a clean checkout of main on this machine (Windows env-specific) and are untouched by this PR.

🤖 Generated with Claude Code

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Note

Low Risk
Localized display and message normalization for Codex errors; no auth or persistence schema changes, and debugging payloads remain in event detail.

Overview
Codex often forwards stringified upstream error JSON as the user-visible message, which showed up as one long token in the chat error banner and overflowed line-clamp-3.

This PR adds extractProviderErrorMessage in @t3tools/shared/providerError (with unit tests) to pull a human-readable message or nested error.message from JSON-shaped strings, including double-encoded payloads, and leaves plain text unchanged.

Server: Codex CodexAdapter and CodexSessionRuntime apply the helper when setting turn.completed.errorMessage, runtime.error / warning messages, and session.lastError from turn failures and provider error notifications. runtime.error still keeps the raw payload in detail.

Web: ThreadErrorBanner unwraps errors again for values stored before the server change, and adds break-words on the banner and tooltip so long strings wrap and clamp correctly.

^{Reviewed by Cursor Bugbot for commit 8d8118e. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Unwrap raw JSON provider error payloads into readable messages in chat

• Adds extractProviderErrorMessage in providerError.ts that parses JSON error bodies from providers, extracts a human-readable message string, and recursively unwraps double-encoded payloads, returning the original input unchanged for non-JSON or unrecognized formats.
• Applies extractProviderErrorMessage in CodexAdapter.ts and CodexSessionRuntime.ts so turn/completed and error runtime events carry unwrapped messages.
• Updates ThreadErrorBanner.tsx to unwrap previously persisted raw JSON errors at render time and adds break-words to prevent long-token overflow.

^{Macroscope summarized 8d8118e.}

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Approvability

Verdict: Approved

This PR adds a defensive utility to extract readable messages from JSON error payloads, improving error message UX. The changes are self-contained, well-tested, and don't alter when errors occur or error handling behavior - only how messages are displayed.

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