muse-spark-1.2-contributor-free returned HTTP 500 on /zen/v1/chat/completions.
The model is only served by /zen/v1/responses, so route it there via a per-model
targetFormat and normalize the Chat fields the Responses API rejects
(max_tokens -> max_output_tokens, reasoning_effort -> reasoning{effort,summary}),
clamping max/ultra down to the highest effort the model accepts (xhigh).
Routing stays per-model: the other free models (big-pickle, hy3-free, mimo,
nemotron, laguna) are not served by /responses and keep /chat/completions.
Mirror the official opencode CLI fingerprint (User-Agent, x-opencode-session, x-opencode-request, x-opencode-project) on free-tier requests so the Console no longer classifies traffic as an unidentified client and rate-limits it with FreeUsageLimitError / HTTP 429.
Session id resolves conversation-stable via resolveSessionId (client session to assistant-text hash to connection) to preserve prompt caching, normalized into opencode ses_ format with a generated fallback. When the downstream client is already opencode, its headers are forwarded as-is.
CHAT_URL and opencode buildUrl base now read from PROVIDERS instead of repeating
the literal. Values identical; providers byte-for-byte + gate clean.
Co-authored-by: Cursor <cursoragent@cursor.com>
## Features
- Add Qoder provider: device-flow OAuth, COSY signing, WAF-bypass body encoding, live model catalog, dashboard quota tracker, 11 models (#1372)
- Add new models: Claude Opus 4.8 (Claude Code), GPT 5.4 Mini (Codex)
## Fixes
- DeepSeek thinking mode: echo `reasoning_content` back on follow-up/tool-call turns so OpenCode-free and custom providers no longer 400 with "reasoning_content must be passed back" (#1543)
- Reasoning injector: match deepseek/kimi model ids case-insensitively (covers custom providers using capitalized model names)
- OpenCode suggested-models: include free models without the `-free` suffix, e.g. `big-pickle` (#1535)
## Improvements
- Codex: trim sunset models, keep gpt-5.5 / gpt-5.4 / gpt-5.3-codex family, add gpt-5.4-mini
- volcengine-ark: refresh model list (add DeepSeek-V4-Flash/Pro, drop EOL entries)
- Lower stream stall timeout 35s → 30s for faster hang detection
