fix: forward reasoning_effort for custom providers (GLM-5.2 on ARK)

- Add 'max' to VALID_REASONING_EFFORTS (GLM-5.2 native parameter)
- Emit top-level reasoning_effort string for custom providers
- Stop hardcoding 'medium' in legacy extra_body.reasoning, use actual effort

Custom providers (e.g. GLM-5.2 on Volcengine ARK) silently dropped
reasoning_effort — the value never reached the upstream API. Kimi,
TokenHub, and LM Studio all had dedicated branches for this, but
custom providers had none.

agent/transports/chat_completions.py

@@ -377,6 +377,22 @@ class ChatCompletionsTransport(ProviderTransport):
             if _lm_effort is not None:
                 api_kwargs["reasoning_effort"] = _lm_effort
 
+        # Custom provider (e.g. GLM-5.2 on ARK): send top-level reasoning_effort
+        # string so the upstream API receives its native parameter format.
+        if params.get("is_custom_provider", False):
+            _custom_thinking_off = bool(
+                reasoning_config
+                and isinstance(reasoning_config, dict)
+                and reasoning_config.get("enabled") is False
+            )
+            if not _custom_thinking_off:
+                _custom_effort = "medium"
+                if reasoning_config and isinstance(reasoning_config, dict):
+                    _custom_effort = (
+                        reasoning_config.get("effort", "medium") or "medium"
+                    )
+                api_kwargs["reasoning_effort"] = _custom_effort
+
         # extra_body assembly
         extra_body: dict[str, Any] = {}
 
@@ -423,7 +439,10 @@ class ChatCompletionsTransport(ProviderTransport):
                 if gh_reasoning is not None:
                     extra_body["reasoning"] = gh_reasoning
             else:
-                extra_body["reasoning"] = {"enabled": True, "effort": "medium"}
+                _effort = "medium"
+                if reasoning_config and isinstance(reasoning_config, dict):
+                    _effort = reasoning_config.get("effort", "medium") or "medium"
+                extra_body["reasoning"] = {"enabled": True, "effort": _effort}
 
         if provider_name == "gemini":
             raw_thinking_config = _build_gemini_thinking_config(model, reasoning_config)

hermes_constants.py

@@ -791,7 +791,7 @@ def apply_subprocess_home_env(env: dict[str, str]) -> None:
         env["HOME"] = home
 
 
-VALID_REASONING_EFFORTS = ("minimal", "low", "medium", "high", "xhigh")
+VALID_REASONING_EFFORTS = ("minimal", "low", "medium", "high", "xhigh", "max")
 
 
 def parse_reasoning_effort(effort) -> dict | None: