Merge main branch with ExtraFields support into ZAI provider branch

This combines:
- PR #41: ZAI provider (and XAI, Groq, Cerebras, Huggingface providers)
- ExtraFields support for OpenAI and OpenAI-compatible providers

The ZAI provider uses openaicompat under the hood, so it will
automatically benefit from ExtraFields for Z.AI GLM thinking mode.

Author: OutBot CI

LICENSE

@@ -175,28 +175,3 @@
       of your accepting any such warranty or additional liability.
 
    END OF TERMS AND CONDITIONS
-
-   APPENDIX: How to apply the Apache License to your work.
-
-      To apply the Apache License to your work, attach the following
-      boilerplate notice, with the fields enclosed by brackets "[]"
-      replaced with your own identifying information. (Don't include
-      the brackets!)  The text should be enclosed in the appropriate
-      comment syntax for the file format. We also recommend that a
-      file or class name and description of purpose be included on the
-      same "printed page" as the copyright notice for easier
-      identification within third-party archives.
-
-   Copyright 2025 Charmbracelet, Inc.
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.

NOTICE

@@ -1,7 +1,13 @@
-Fantasy
 Copyright 2025 Charmbracelet, Inc.
 
-Part of the Charm open source ecosystem.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
 
-This product includes software developed by Charmbracelet, Inc.
-(http://charm.land)
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.

providers/openai/language_model_hooks.go

@@ -99,6 +99,11 @@ func DefaultPrepareCallFunc(model fantasy.LanguageModel, params *openai.ChatComp
 		}
 		params.Metadata = metadata
 	}
+
+	// Apply extra fields for custom OpenAI-compatible APIs (e.g., Z.AI GLM thinking mode)
+	if providerOptions.ExtraFields != nil && len(providerOptions.ExtraFields) > 0 {
+		params.SetExtraFields(providerOptions.ExtraFields)
+	}
 	if providerOptions.PromptCacheKey != nil {
 		params.PromptCacheKey = param.NewOpt(*providerOptions.PromptCacheKey)
 	}

providers/openai/provider_options.go

@@ -47,6 +47,9 @@ type ProviderOptions struct {
 	SafetyIdentifier    *string          `json:"safety_identifier"`
 	ServiceTier         *string          `json:"service_tier"`
 	StructuredOutputs   *bool            `json:"structured_outputs"`
+	// ExtraFields allows passing arbitrary additional parameters to OpenAI-compatible APIs
+	// that require custom fields not part of the standard OpenAI API specification.
+	ExtraFields map[string]any `json:"extra_fields,omitempty"`
 }
 
 // Options implements the ProviderOptions interface.

providers/openaicompat/language_model_hooks.go

@@ -41,6 +41,12 @@ func PrepareCallFunc(_ fantasy.LanguageModel, params *openaisdk.ChatCompletionNe
 	if providerOptions.User != nil {
 		params.User = param.NewOpt(*providerOptions.User)
 	}
+
+	// Apply extra fields for custom OpenAI-compatible APIs (e.g., Z.AI GLM thinking mode)
+	if providerOptions.ExtraFields != nil && len(providerOptions.ExtraFields) > 0 {
+		params.SetExtraFields(providerOptions.ExtraFields)
+	}
+
 	return nil, nil
 }
 

providers/openaicompat/provider_options.go

@@ -10,6 +10,9 @@ import (
 type ProviderOptions struct {
 	User            *string                 `json:"user"`
 	ReasoningEffort *openai.ReasoningEffort `json:"reasoning_effort"`
+	// ExtraFields allows passing arbitrary additional parameters to custom OpenAI-compatible APIs
+	// that require custom fields not part of the standard OpenAI API specification.
+	ExtraFields map[string]any `json:"extra_fields,omitempty"`
 }
 
 // ReasoningData represents reasoning data for OpenAI-compatible provider.