zen/go/v1 upstream (Console Go) rejects Codex tool schemas that omit required - Missing 'limit'

issue draft (anomalyco/opencode)

Title:

zen/go/v1 upstream ("Console Go") rejects Codex tool schemas that omit required (Missing 'limit')

Body:

When using muse-spark-1.2-contributor through https://opencode.ai/zen/go/v1
with Codex Desktop, requests fail with:

Error from provider (Console Go): Upstream request failed: [invalid_request_error] 'required' is required to be supplied and to be an array including every key in properties. Missing 'limit'.

The request is a standard Responses API call. The limit property comes from
Codex Desktop's own list_threads / list_archived_threads tool schemas
(additionalProperties: false, no required). Simple requests without tools
work fine, and the same request succeeds for other models on the same gateway
(e.g. deepseek-v4-flash).

The upstream's strict schema validation rejects schemas that OpenAI itself
accepts for non-strict tools. Please either relax the validation to only apply
when the tool is explicitly marked strict: true, or surface which field
failed so clients can adapt. Repro payloads are in the linked Codex issue.

Related: #37231, #43163, #43557.

Start with the zen/go/v1 Responses API request path and the reproduction payloads in the linked Codex issue. Confirm whether non-strict tool schemas are being validated as strict, then check how the upstream error is surfaced. Done means non-strict schemas are accepted or the failing field is reported clearly, with regression coverage for the reported request.