feat(api): Add support for claude-mythos-preview

stainless-app[bot] · stainless-app[bot] · commit 471f3015371a · 2026-04-07T17:53:08.000Z
diff --git a/.stats.yml b/.stats.yml
@@ -1,4 +1,4 @@
 configured_endpoints: 31
-openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/anthropic%2Fanthropic-efe26b096126c693462514b8cbd3ec3e376569232becbfb730cd26fb31c7c7e3.yml
+openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/anthropic%2Fanthropic-04225437444990f383d0581df2f07022baab6ad510de0f3a8bd6b07c38d83cc9.yml
 openapi_spec_hash: cae9199aabfd7b87f0ff2dcc10760c92
-config_hash: e1ebf6470ea96e5b7bf02520fbeeed0a
+config_hash: fcc34074db6eaf64bc99b578c6c82c61
diff --git a/src/Beta/Messages/Batches/BatchCreateParams/Request/Params.php b/src/Beta/Messages/Batches/BatchCreateParams/Request/Params.php
@@ -264,6 +264,8 @@ final class Params implements BaseModel
     public string|array|null $system;
 
     /**
+     * @deprecated Deprecated. Models released after Claude Opus 4.6 do not support setting temperature. A value of 1.0 of will be accepted for backwards compatibility, all other values will be rejected with a 400 error.
+     *
      * Amount of randomness injected into the response.
      *
      * Defaults to `1.0`. Ranges from `0.0` to `1.0`. Use `temperature` closer to `0.0` for analytical / multiple choice, and closer to `1.0` for creative and generative tasks.
@@ -362,6 +364,8 @@ final class Params implements BaseModel
     public ?array $tools;
 
     /**
+     * @deprecated Deprecated. Models released after Claude Opus 4.6 do not accept top_k; any value will be rejected with a 400 error.
+     *
      * Only sample from the top K options for each subsequent token.
      *
      * Used to remove "long tail" low probability responses. [Learn more technical details here](https://towardsdatascience.com/how-to-sample-from-language-models-682bceb97277).
@@ -372,6 +376,8 @@ final class Params implements BaseModel
     public ?int $topK;
 
     /**
+     * @deprecated Deprecated. Models released after Claude Opus 4.6 do not support setting top_p. A value >= 0.99 will be accepted for backwards compatibility, all other values will be rejected with a 400 error.
+     *
      * Use nucleus sampling.
      *
      * In nucleus sampling, we compute the cumulative distribution over all the options for each subsequent token in decreasing probability order and cut it off once it reaches a particular probability specified by `top_p`. You should either alter `temperature` or `top_p`, but not both.
diff --git a/src/Beta/Messages/MessageCreateParams.php b/src/Beta/Messages/MessageCreateParams.php
@@ -245,6 +245,8 @@ final class MessageCreateParams implements BaseModel
     public string|array|null $system;
 
     /**
+     * @deprecated Deprecated. Models released after Claude Opus 4.6 do not support setting temperature. A value of 1.0 of will be accepted for backwards compatibility, all other values will be rejected with a 400 error.
+     *
      * Amount of randomness injected into the response.
      *
      * Defaults to `1.0`. Ranges from `0.0` to `1.0`. Use `temperature` closer to `0.0` for analytical / multiple choice, and closer to `1.0` for creative and generative tasks.
@@ -343,6 +345,8 @@ final class MessageCreateParams implements BaseModel
     public ?array $tools;
 
     /**
+     * @deprecated Deprecated. Models released after Claude Opus 4.6 do not accept top_k; any value will be rejected with a 400 error.
+     *
      * Only sample from the top K options for each subsequent token.
      *
      * Used to remove "long tail" low probability responses. [Learn more technical details here](https://towardsdatascience.com/how-to-sample-from-language-models-682bceb97277).
@@ -353,6 +357,8 @@ final class MessageCreateParams implements BaseModel
     public ?int $topK;
 
     /**
+     * @deprecated Deprecated. Models released after Claude Opus 4.6 do not support setting top_p. A value >= 0.99 will be accepted for backwards compatibility, all other values will be rejected with a 400 error.
+     *
      * Use nucleus sampling.
      *
      * In nucleus sampling, we compute the cumulative distribution over all the options for each subsequent token in decreasing probability order and cut it off once it reaches a particular probability specified by `top_p`. You should either alter `temperature` or `top_p`, but not both.
diff --git a/src/Messages/Batches/BatchCreateParams/Request/Params.php b/src/Messages/Batches/BatchCreateParams/Request/Params.php
@@ -214,6 +214,8 @@ final class Params implements BaseModel
     public string|array|null $system;
 
     /**
+     * @deprecated Deprecated. Models released after Claude Opus 4.6 do not support setting temperature. A value of 1.0 of will be accepted for backwards compatibility, all other values will be rejected with a 400 error.
+     *
      * Amount of randomness injected into the response.
      *
      * Defaults to `1.0`. Ranges from `0.0` to `1.0`. Use `temperature` closer to `0.0` for analytical / multiple choice, and closer to `1.0` for creative and generative tasks.
@@ -312,6 +314,8 @@ final class Params implements BaseModel
     public ?array $tools;
 
     /**
+     * @deprecated Deprecated. Models released after Claude Opus 4.6 do not accept top_k; any value will be rejected with a 400 error.
+     *
      * Only sample from the top K options for each subsequent token.
      *
      * Used to remove "long tail" low probability responses. [Learn more technical details here](https://towardsdatascience.com/how-to-sample-from-language-models-682bceb97277).
@@ -322,6 +326,8 @@ final class Params implements BaseModel
     public ?int $topK;
 
     /**
+     * @deprecated Deprecated. Models released after Claude Opus 4.6 do not support setting top_p. A value >= 0.99 will be accepted for backwards compatibility, all other values will be rejected with a 400 error.
+     *
      * Use nucleus sampling.
      *
      * In nucleus sampling, we compute the cumulative distribution over all the options for each subsequent token in decreasing probability order and cut it off once it reaches a particular probability specified by `top_p`. You should either alter `temperature` or `top_p`, but not both.
diff --git a/src/Messages/MessageCreateParams.php b/src/Messages/MessageCreateParams.php
@@ -196,6 +196,8 @@ final class MessageCreateParams implements BaseModel
     public string|array|null $system;
 
     /**
+     * @deprecated Deprecated. Models released after Claude Opus 4.6 do not support setting temperature. A value of 1.0 of will be accepted for backwards compatibility, all other values will be rejected with a 400 error.
+     *
      * Amount of randomness injected into the response.
      *
      * Defaults to `1.0`. Ranges from `0.0` to `1.0`. Use `temperature` closer to `0.0` for analytical / multiple choice, and closer to `1.0` for creative and generative tasks.
@@ -294,6 +296,8 @@ final class MessageCreateParams implements BaseModel
     public ?array $tools;
 
     /**
+     * @deprecated Deprecated. Models released after Claude Opus 4.6 do not accept top_k; any value will be rejected with a 400 error.
+     *
      * Only sample from the top K options for each subsequent token.
      *
      * Used to remove "long tail" low probability responses. [Learn more technical details here](https://towardsdatascience.com/how-to-sample-from-language-models-682bceb97277).
@@ -304,6 +308,8 @@ final class MessageCreateParams implements BaseModel
     public ?int $topK;
 
     /**
+     * @deprecated Deprecated. Models released after Claude Opus 4.6 do not support setting top_p. A value >= 0.99 will be accepted for backwards compatibility, all other values will be rejected with a 400 error.
+     *
      * Use nucleus sampling.
      *
      * In nucleus sampling, we compute the cumulative distribution over all the options for each subsequent token in decreasing probability order and cut it off once it reaches a particular probability specified by `top_p`. You should either alter `temperature` or `top_p`, but not both.
diff --git a/src/Messages/Model.php b/src/Messages/Model.php
@@ -14,6 +14,8 @@
 enum Model: string
 {
     // Anthropic model identifiers
+  
+    case CLAUDE_MYTHOS_PREVIEW = 'claude-mythos-preview';
 
     case CLAUDE_OPUS_4_6 = 'claude-opus-4-6';
 
diff --git a/tests/Services/Beta/MessagesTest.php b/tests/Services/Beta/MessagesTest.php
@@ -140,7 +140,7 @@ public function testCountTokens(): void
     {
         $result = $this->client->beta->messages->countTokens(
             messages: [['content' => 'string', 'role' => 'user']],
-            model: 'claude-opus-4-6',
+            model: 'claude-mythos-preview',
         );
 
         // @phpstan-ignore-next-line method.alreadyNarrowedType
@@ -152,7 +152,7 @@ public function testCountTokensWithOptionalParams(): void
     {
         $result = $this->client->beta->messages->countTokens(
             messages: [['content' => 'string', 'role' => 'user']],
-            model: 'claude-opus-4-6',
+            model: 'claude-mythos-preview',
             cacheControl: ['type' => 'ephemeral', 'ttl' => '5m'],
             contextManagement: [
                 'edits' => [
diff --git a/tests/Services/MessagesTest.php b/tests/Services/MessagesTest.php
@@ -109,7 +109,7 @@ public function testCountTokens(): void
     {
         $result = $this->client->messages->countTokens(
             messages: [['content' => 'string', 'role' => 'user']],
-            model: 'claude-opus-4-6',
+            model: 'claude-mythos-preview',
         );
 
         // @phpstan-ignore-next-line method.alreadyNarrowedType
@@ -121,7 +121,7 @@ public function testCountTokensWithOptionalParams(): void
     {
         $result = $this->client->messages->countTokens(
             messages: [['content' => 'string', 'role' => 'user']],
-            model: 'claude-opus-4-6',
+            model: 'claude-mythos-preview',
             cacheControl: ['type' => 'ephemeral', 'ttl' => '5m'],
             outputConfig: [
                 'effort' => 'low',

Original file line number	Diff line number	Diff line change
`@@ -14,6 +14,8 @@`
`14`	`14`	`enum Model: string`
`15`	`15`	`{`
`16`	`16`	`// Anthropic model identifiers`
	`17`	`+`
	`18`	`+ case CLAUDE_MYTHOS_PREVIEW = 'claude-mythos-preview';`
`17`	`19`
`18`	`20`	`case CLAUDE_OPUS_4_6 = 'claude-opus-4-6';`
`19`	`21`