fix: Claude Opus 5 support for claude_code and anthropic providers

crates/forge_app/src/dto/anthropic/response.rs

@@ -84,8 +84,8 @@ fn get_context_length(model_id: &str) -> Option<u64> {
         return Some(1_000_000);
     }
 
-    // Claude Sonnet 5 (1M context)
-    if model_id.starts_with("claude-sonnet-5") {
+    // Claude Sonnet 5 and Opus 5 (1M context)
+    if model_id.starts_with("claude-sonnet-5") || model_id.starts_with("claude-opus-5") {
         return Some(1_000_000);
     }
 

crates/forge_app/src/transformers/model_specific_reasoning.rs

@@ -27,14 +27,15 @@ impl ModelSpecificReasoning {
 
     fn family(&self) -> AnthropicModelFamily {
         let id = self.model_id.to_lowercase();
-        if id.contains("opus-4-8")
+        if id.contains("opus-5")
+            || id.contains("opus-4-8")
             || id.contains("48-opus")
             || id.contains("opus-4-7")
             || id.contains("47-opus")
             || id.contains("mythos")
             || id.contains("fable")
         {
-            // Opus 4.8 shares Opus 4.7's API contract: adaptive thinking only
+            // Opus 5 and Opus 4.8 share Opus 4.7's API contract: adaptive thinking only
             // (legacy `budget_tokens` returns 400) and non-default sampling
             // params (`temperature`/`top_p`/`top_k`) return 400.
             AnthropicModelFamily::AdaptiveOnly
@@ -188,6 +189,29 @@ mod tests {
         assert_eq!(actual, expected);
     }
 
+    #[test]
+    fn test_opus_5_drops_max_tokens_and_sampling_params() {
+        // Opus 5 shares the Opus 4.7/4.8 API contract: adaptive thinking only,
+        // legacy `budget_tokens` and non-default sampling params return 400.
+        let fixture = fixture_context_with_sampling().reasoning(ReasoningConfig {
+            enabled: Some(true),
+            max_tokens: Some(8000),
+            effort: Some(Effort::XHigh),
+            exclude: Some(true),
+        });
+
+        let actual = ModelSpecificReasoning::new("claude-opus-5").transform(fixture);
+
+        let expected = Context::default().reasoning(ReasoningConfig {
+            enabled: Some(true),
+            max_tokens: None,
+            effort: Some(Effort::XHigh),
+            exclude: Some(true),
+        });
+
+        assert_eq!(actual, expected);
+    }
+
     #[test]
     fn test_opus_4_8_strips_sampling_even_without_reasoning() {
         let fixture = fixture_context_with_sampling();

crates/forge_repo/src/provider/anthropic.rs

@@ -92,13 +92,15 @@ impl<H: HttpInfra> Anthropic<H> {
 }
 
 /// Returns false when the model auto-enables interleaved thinking through
-/// adaptive thinking (Opus 4.8, Opus 4.7, Opus 4.6, Sonnet 5, Sonnet 4.6). When
+/// adaptive thinking (Opus 5, Opus 4.8, Opus 4.7, Opus 4.6, Sonnet 5, Sonnet
+/// 4.6). When
 /// the model is unknown (e.g., listing endpoints), the flag is included because
 /// it is harmless on non-chat endpoints and necessary on older chat models.
 fn interleaved_thinking_required(model: Option<&ModelId>) -> bool {
     let Some(model) = model else { return true };
     let id = model.as_str().to_lowercase();
-    !(id.contains("opus-4-8")
+    !(id.contains("opus-5")
+        || id.contains("opus-4-8")
         || id.contains("opus-4-7")
         || id.contains("opus-4-6")
         || id.contains("sonnet-4-6")
@@ -837,6 +839,7 @@ mod tests {
         );
 
         for model_id in [
+            "claude-opus-5",
             "claude-opus-4-8",
             "claude-opus-4-7",
             "claude-opus-4-6",

crates/forge_repo/src/provider/provider.json

@@ -765,6 +765,16 @@
         "supports_reasoning": true,
         "input_modalities": ["text", "image"]
       },
+      {
+        "id": "claude-opus-5",
+        "name": "Claude Opus 5",
+        "description": "Thoughtful and proactive model approaching frontier intelligence at half the price",
+        "context_length": 1000000,
+        "tools_supported": true,
+        "supports_parallel_tool_calls": true,
+        "supports_reasoning": true,
+        "input_modalities": ["text", "image"]
+      },
       {
         "id": "claude-opus-4-8",
         "name": "Claude Opus 4.8",