# Models ## List Models `client.Beta.Models.List(ctx, params) (*Page[BetaModelInfo], error)` **get** `/v1/models` List available models. The Models API response can be used to determine which models are available for use in the API. More recently released models are listed first. ### Parameters - `params BetaModelListParams` - `AfterID param.Field[string]` Query param: ID of the object to use as a cursor for pagination. When provided, returns the page of results immediately after this object. - `BeforeID param.Field[string]` Query param: ID of the object to use as a cursor for pagination. When provided, returns the page of results immediately before this object. - `Limit param.Field[int64]` Query param: Number of items to return per page. Defaults to `20`. Ranges from `1` to `1000`. - `Betas param.Field[[]AnthropicBeta]` Header param: Optional header to specify the beta version(s) you want to use. - `string` - `type AnthropicBeta string` - `const AnthropicBetaMessageBatches2024_09_24 AnthropicBeta = "message-batches-2024-09-24"` - `const AnthropicBetaPromptCaching2024_07_31 AnthropicBeta = "prompt-caching-2024-07-31"` - `const AnthropicBetaComputerUse2024_10_22 AnthropicBeta = "computer-use-2024-10-22"` - `const AnthropicBetaComputerUse2025_01_24 AnthropicBeta = "computer-use-2025-01-24"` - `const AnthropicBetaPDFs2024_09_25 AnthropicBeta = "pdfs-2024-09-25"` - `const AnthropicBetaTokenCounting2024_11_01 AnthropicBeta = "token-counting-2024-11-01"` - `const AnthropicBetaTokenEfficientTools2025_02_19 AnthropicBeta = "token-efficient-tools-2025-02-19"` - `const AnthropicBetaOutput128k2025_02_19 AnthropicBeta = "output-128k-2025-02-19"` - `const AnthropicBetaFilesAPI2025_04_14 AnthropicBeta = "files-api-2025-04-14"` - `const AnthropicBetaMCPClient2025_04_04 AnthropicBeta = "mcp-client-2025-04-04"` - `const AnthropicBetaMCPClient2025_11_20 AnthropicBeta = "mcp-client-2025-11-20"` - `const AnthropicBetaDevFullThinking2025_05_14 AnthropicBeta = "dev-full-thinking-2025-05-14"` - `const AnthropicBetaInterleavedThinking2025_05_14 AnthropicBeta = "interleaved-thinking-2025-05-14"` - `const AnthropicBetaCodeExecution2025_05_22 AnthropicBeta = "code-execution-2025-05-22"` - `const AnthropicBetaExtendedCacheTTL2025_04_11 AnthropicBeta = "extended-cache-ttl-2025-04-11"` - `const AnthropicBetaContext1m2025_08_07 AnthropicBeta = "context-1m-2025-08-07"` - `const AnthropicBetaContextManagement2025_06_27 AnthropicBeta = "context-management-2025-06-27"` - `const AnthropicBetaModelContextWindowExceeded2025_08_26 AnthropicBeta = "model-context-window-exceeded-2025-08-26"` - `const AnthropicBetaSkills2025_10_02 AnthropicBeta = "skills-2025-10-02"` - `const AnthropicBetaFastMode2026_02_01 AnthropicBeta = "fast-mode-2026-02-01"` - `const AnthropicBetaOutput300k2026_03_24 AnthropicBeta = "output-300k-2026-03-24"` - `const AnthropicBetaUserProfiles2026_03_24 AnthropicBeta = "user-profiles-2026-03-24"` - `const AnthropicBetaAdvisorTool2026_03_01 AnthropicBeta = "advisor-tool-2026-03-01"` - `const AnthropicBetaManagedAgents2026_04_01 AnthropicBeta = "managed-agents-2026-04-01"` - `const AnthropicBetaCacheDiagnosis2026_04_07 AnthropicBeta = "cache-diagnosis-2026-04-07"` - `const AnthropicBetaThinkingTokenCount2026_05_13 AnthropicBeta = "thinking-token-count-2026-05-13"` - `const AnthropicBetaServerSideFallback2026_06_01 AnthropicBeta = "server-side-fallback-2026-06-01"` - `const AnthropicBetaFallbackCredit2026_06_01 AnthropicBeta = "fallback-credit-2026-06-01"` ### Returns - `type BetaModelInfo struct{…}` - `ID string` Unique model identifier. - `AllowedFallbackModels []string` Model IDs this model accepts as `fallbacks[i].model` on the Messages API. An empty list means the `fallbacks` parameter is not supported for this model as primary. - `Capabilities BetaModelCapabilities` Model capability information. - `Batch BetaCapabilitySupport` Whether the model supports the Batch API. - `Supported bool` Whether this capability is supported by the model. - `Citations BetaCapabilitySupport` Whether the model supports citation generation. - `CodeExecution BetaCapabilitySupport` Whether the model supports code execution tools. - `ContextManagement BetaContextManagementCapability` Context management support and available strategies. - `ClearThinking20251015 BetaCapabilitySupport` Indicates whether a capability is supported. - `ClearToolUses20250919 BetaCapabilitySupport` Indicates whether a capability is supported. - `Compact20260112 BetaCapabilitySupport` Indicates whether a capability is supported. - `Supported bool` Whether this capability is supported by the model. - `Effort BetaEffortCapability` Effort (reasoning_effort) support and available levels. - `High BetaCapabilitySupport` Whether the model supports high effort level. - `Low BetaCapabilitySupport` Whether the model supports low effort level. - `Max BetaCapabilitySupport` Whether the model supports max effort level. - `Medium BetaCapabilitySupport` Whether the model supports medium effort level. - `Supported bool` Whether this capability is supported by the model. - `Xhigh BetaCapabilitySupport` Indicates whether a capability is supported. - `ImageInput BetaCapabilitySupport` Whether the model accepts image content blocks. - `PDFInput BetaCapabilitySupport` Whether the model accepts PDF content blocks. - `StructuredOutputs BetaCapabilitySupport` Whether the model supports structured output / JSON mode / strict tool schemas. - `Thinking BetaThinkingCapability` Thinking capability and supported type configurations. - `Supported bool` Whether this capability is supported by the model. - `Types BetaThinkingTypes` Supported thinking type configurations. - `Adaptive BetaCapabilitySupport` Whether the model supports thinking with type 'adaptive' (auto). - `Enabled BetaCapabilitySupport` Whether the model supports thinking with type 'enabled'. - `CreatedAt Time` RFC 3339 datetime string representing the time at which the model was released. May be set to an epoch value if the release date is unknown. - `DisplayName string` A human-readable name for the model. - `MaxInputTokens int64` Maximum input context window size in tokens for this model. - `MaxTokens int64` Maximum value for the `max_tokens` parameter when using this model. - `Type Model` Object type. For Models, this is always `"model"`. - `const ModelModel Model = "model"` ### Example ```go package main import ( "context" "fmt" "github.com/anthropics/anthropic-sdk-go" "github.com/anthropics/anthropic-sdk-go/option" ) func main() { client := anthropic.NewClient( option.WithAPIKey("my-anthropic-api-key"), ) page, err := client.Beta.Models.List(context.TODO(), anthropic.BetaModelListParams{ }) if err != nil { panic(err.Error()) } fmt.Printf("%+v\n", page) } ``` #### Response ```json { "data": [ { "id": "claude-opus-4-6", "allowed_fallback_models": [ "string" ], "capabilities": { "batch": { "supported": true }, "citations": { "supported": true }, "code_execution": { "supported": true }, "context_management": { "clear_thinking_20251015": { "supported": true }, "clear_tool_uses_20250919": { "supported": true }, "compact_20260112": { "supported": true }, "supported": true }, "effort": { "high": { "supported": true }, "low": { "supported": true }, "max": { "supported": true }, "medium": { "supported": true }, "supported": true, "xhigh": { "supported": true } }, "image_input": { "supported": true }, "pdf_input": { "supported": true }, "structured_outputs": { "supported": true }, "thinking": { "supported": true, "types": { "adaptive": { "supported": true }, "enabled": { "supported": true } } } }, "created_at": "2026-02-04T00:00:00Z", "display_name": "Claude Opus 4.6", "max_input_tokens": 0, "max_tokens": 0, "type": "model" } ], "first_id": "first_id", "has_more": true, "last_id": "last_id" } ``` ## Get a Model `client.Beta.Models.Get(ctx, modelID, query) (*BetaModelInfo, error)` **get** `/v1/models/{model_id}` Get a specific model. The Models API response can be used to determine information about a specific model or resolve a model alias to a model ID. ### Parameters - `modelID string` Model identifier or alias. - `query BetaModelGetParams` - `Betas param.Field[[]AnthropicBeta]` Optional header to specify the beta version(s) you want to use. - `string` - `type AnthropicBeta string` - `const AnthropicBetaMessageBatches2024_09_24 AnthropicBeta = "message-batches-2024-09-24"` - `const AnthropicBetaPromptCaching2024_07_31 AnthropicBeta = "prompt-caching-2024-07-31"` - `const AnthropicBetaComputerUse2024_10_22 AnthropicBeta = "computer-use-2024-10-22"` - `const AnthropicBetaComputerUse2025_01_24 AnthropicBeta = "computer-use-2025-01-24"` - `const AnthropicBetaPDFs2024_09_25 AnthropicBeta = "pdfs-2024-09-25"` - `const AnthropicBetaTokenCounting2024_11_01 AnthropicBeta = "token-counting-2024-11-01"` - `const AnthropicBetaTokenEfficientTools2025_02_19 AnthropicBeta = "token-efficient-tools-2025-02-19"` - `const AnthropicBetaOutput128k2025_02_19 AnthropicBeta = "output-128k-2025-02-19"` - `const AnthropicBetaFilesAPI2025_04_14 AnthropicBeta = "files-api-2025-04-14"` - `const AnthropicBetaMCPClient2025_04_04 AnthropicBeta = "mcp-client-2025-04-04"` - `const AnthropicBetaMCPClient2025_11_20 AnthropicBeta = "mcp-client-2025-11-20"` - `const AnthropicBetaDevFullThinking2025_05_14 AnthropicBeta = "dev-full-thinking-2025-05-14"` - `const AnthropicBetaInterleavedThinking2025_05_14 AnthropicBeta = "interleaved-thinking-2025-05-14"` - `const AnthropicBetaCodeExecution2025_05_22 AnthropicBeta = "code-execution-2025-05-22"` - `const AnthropicBetaExtendedCacheTTL2025_04_11 AnthropicBeta = "extended-cache-ttl-2025-04-11"` - `const AnthropicBetaContext1m2025_08_07 AnthropicBeta = "context-1m-2025-08-07"` - `const AnthropicBetaContextManagement2025_06_27 AnthropicBeta = "context-management-2025-06-27"` - `const AnthropicBetaModelContextWindowExceeded2025_08_26 AnthropicBeta = "model-context-window-exceeded-2025-08-26"` - `const AnthropicBetaSkills2025_10_02 AnthropicBeta = "skills-2025-10-02"` - `const AnthropicBetaFastMode2026_02_01 AnthropicBeta = "fast-mode-2026-02-01"` - `const AnthropicBetaOutput300k2026_03_24 AnthropicBeta = "output-300k-2026-03-24"` - `const AnthropicBetaUserProfiles2026_03_24 AnthropicBeta = "user-profiles-2026-03-24"` - `const AnthropicBetaAdvisorTool2026_03_01 AnthropicBeta = "advisor-tool-2026-03-01"` - `const AnthropicBetaManagedAgents2026_04_01 AnthropicBeta = "managed-agents-2026-04-01"` - `const AnthropicBetaCacheDiagnosis2026_04_07 AnthropicBeta = "cache-diagnosis-2026-04-07"` - `const AnthropicBetaThinkingTokenCount2026_05_13 AnthropicBeta = "thinking-token-count-2026-05-13"` - `const AnthropicBetaServerSideFallback2026_06_01 AnthropicBeta = "server-side-fallback-2026-06-01"` - `const AnthropicBetaFallbackCredit2026_06_01 AnthropicBeta = "fallback-credit-2026-06-01"` ### Returns - `type BetaModelInfo struct{…}` - `ID string` Unique model identifier. - `AllowedFallbackModels []string` Model IDs this model accepts as `fallbacks[i].model` on the Messages API. An empty list means the `fallbacks` parameter is not supported for this model as primary. - `Capabilities BetaModelCapabilities` Model capability information. - `Batch BetaCapabilitySupport` Whether the model supports the Batch API. - `Supported bool` Whether this capability is supported by the model. - `Citations BetaCapabilitySupport` Whether the model supports citation generation. - `CodeExecution BetaCapabilitySupport` Whether the model supports code execution tools. - `ContextManagement BetaContextManagementCapability` Context management support and available strategies. - `ClearThinking20251015 BetaCapabilitySupport` Indicates whether a capability is supported. - `ClearToolUses20250919 BetaCapabilitySupport` Indicates whether a capability is supported. - `Compact20260112 BetaCapabilitySupport` Indicates whether a capability is supported. - `Supported bool` Whether this capability is supported by the model. - `Effort BetaEffortCapability` Effort (reasoning_effort) support and available levels. - `High BetaCapabilitySupport` Whether the model supports high effort level. - `Low BetaCapabilitySupport` Whether the model supports low effort level. - `Max BetaCapabilitySupport` Whether the model supports max effort level. - `Medium BetaCapabilitySupport` Whether the model supports medium effort level. - `Supported bool` Whether this capability is supported by the model. - `Xhigh BetaCapabilitySupport` Indicates whether a capability is supported. - `ImageInput BetaCapabilitySupport` Whether the model accepts image content blocks. - `PDFInput BetaCapabilitySupport` Whether the model accepts PDF content blocks. - `StructuredOutputs BetaCapabilitySupport` Whether the model supports structured output / JSON mode / strict tool schemas. - `Thinking BetaThinkingCapability` Thinking capability and supported type configurations. - `Supported bool` Whether this capability is supported by the model. - `Types BetaThinkingTypes` Supported thinking type configurations. - `Adaptive BetaCapabilitySupport` Whether the model supports thinking with type 'adaptive' (auto). - `Enabled BetaCapabilitySupport` Whether the model supports thinking with type 'enabled'. - `CreatedAt Time` RFC 3339 datetime string representing the time at which the model was released. May be set to an epoch value if the release date is unknown. - `DisplayName string` A human-readable name for the model. - `MaxInputTokens int64` Maximum input context window size in tokens for this model. - `MaxTokens int64` Maximum value for the `max_tokens` parameter when using this model. - `Type Model` Object type. For Models, this is always `"model"`. - `const ModelModel Model = "model"` ### Example ```go package main import ( "context" "fmt" "github.com/anthropics/anthropic-sdk-go" "github.com/anthropics/anthropic-sdk-go/option" ) func main() { client := anthropic.NewClient( option.WithAPIKey("my-anthropic-api-key"), ) betaModelInfo, err := client.Beta.Models.Get( context.TODO(), "model_id", anthropic.BetaModelGetParams{ }, ) if err != nil { panic(err.Error()) } fmt.Printf("%+v\n", betaModelInfo.ID) } ``` #### Response ```json { "id": "claude-opus-4-6", "allowed_fallback_models": [ "string" ], "capabilities": { "batch": { "supported": true }, "citations": { "supported": true }, "code_execution": { "supported": true }, "context_management": { "clear_thinking_20251015": { "supported": true }, "clear_tool_uses_20250919": { "supported": true }, "compact_20260112": { "supported": true }, "supported": true }, "effort": { "high": { "supported": true }, "low": { "supported": true }, "max": { "supported": true }, "medium": { "supported": true }, "supported": true, "xhigh": { "supported": true } }, "image_input": { "supported": true }, "pdf_input": { "supported": true }, "structured_outputs": { "supported": true }, "thinking": { "supported": true, "types": { "adaptive": { "supported": true }, "enabled": { "supported": true } } } }, "created_at": "2026-02-04T00:00:00Z", "display_name": "Claude Opus 4.6", "max_input_tokens": 0, "max_tokens": 0, "type": "model" } ``` ## Domain Types ### Beta Capability Support - `type BetaCapabilitySupport struct{…}` Indicates whether a capability is supported. - `Supported bool` Whether this capability is supported by the model. ### Beta Context Management Capability - `type BetaContextManagementCapability struct{…}` Context management capability details. - `ClearThinking20251015 BetaCapabilitySupport` Indicates whether a capability is supported. - `Supported bool` Whether this capability is supported by the model. - `ClearToolUses20250919 BetaCapabilitySupport` Indicates whether a capability is supported. - `Compact20260112 BetaCapabilitySupport` Indicates whether a capability is supported. - `Supported bool` Whether this capability is supported by the model. ### Beta Effort Capability - `type BetaEffortCapability struct{…}` Effort (reasoning_effort) capability details. - `High BetaCapabilitySupport` Whether the model supports high effort level. - `Supported bool` Whether this capability is supported by the model. - `Low BetaCapabilitySupport` Whether the model supports low effort level. - `Max BetaCapabilitySupport` Whether the model supports max effort level. - `Medium BetaCapabilitySupport` Whether the model supports medium effort level. - `Supported bool` Whether this capability is supported by the model. - `Xhigh BetaCapabilitySupport` Indicates whether a capability is supported. ### Beta Model Capabilities - `type BetaModelCapabilities struct{…}` Model capability information. - `Batch BetaCapabilitySupport` Whether the model supports the Batch API. - `Supported bool` Whether this capability is supported by the model. - `Citations BetaCapabilitySupport` Whether the model supports citation generation. - `CodeExecution BetaCapabilitySupport` Whether the model supports code execution tools. - `ContextManagement BetaContextManagementCapability` Context management support and available strategies. - `ClearThinking20251015 BetaCapabilitySupport` Indicates whether a capability is supported. - `ClearToolUses20250919 BetaCapabilitySupport` Indicates whether a capability is supported. - `Compact20260112 BetaCapabilitySupport` Indicates whether a capability is supported. - `Supported bool` Whether this capability is supported by the model. - `Effort BetaEffortCapability` Effort (reasoning_effort) support and available levels. - `High BetaCapabilitySupport` Whether the model supports high effort level. - `Low BetaCapabilitySupport` Whether the model supports low effort level. - `Max BetaCapabilitySupport` Whether the model supports max effort level. - `Medium BetaCapabilitySupport` Whether the model supports medium effort level. - `Supported bool` Whether this capability is supported by the model. - `Xhigh BetaCapabilitySupport` Indicates whether a capability is supported. - `ImageInput BetaCapabilitySupport` Whether the model accepts image content blocks. - `PDFInput BetaCapabilitySupport` Whether the model accepts PDF content blocks. - `StructuredOutputs BetaCapabilitySupport` Whether the model supports structured output / JSON mode / strict tool schemas. - `Thinking BetaThinkingCapability` Thinking capability and supported type configurations. - `Supported bool` Whether this capability is supported by the model. - `Types BetaThinkingTypes` Supported thinking type configurations. - `Adaptive BetaCapabilitySupport` Whether the model supports thinking with type 'adaptive' (auto). - `Enabled BetaCapabilitySupport` Whether the model supports thinking with type 'enabled'. ### Beta Model Info - `type BetaModelInfo struct{…}` - `ID string` Unique model identifier. - `AllowedFallbackModels []string` Model IDs this model accepts as `fallbacks[i].model` on the Messages API. An empty list means the `fallbacks` parameter is not supported for this model as primary. - `Capabilities BetaModelCapabilities` Model capability information. - `Batch BetaCapabilitySupport` Whether the model supports the Batch API. - `Supported bool` Whether this capability is supported by the model. - `Citations BetaCapabilitySupport` Whether the model supports citation generation. - `CodeExecution BetaCapabilitySupport` Whether the model supports code execution tools. - `ContextManagement BetaContextManagementCapability` Context management support and available strategies. - `ClearThinking20251015 BetaCapabilitySupport` Indicates whether a capability is supported. - `ClearToolUses20250919 BetaCapabilitySupport` Indicates whether a capability is supported. - `Compact20260112 BetaCapabilitySupport` Indicates whether a capability is supported. - `Supported bool` Whether this capability is supported by the model. - `Effort BetaEffortCapability` Effort (reasoning_effort) support and available levels. - `High BetaCapabilitySupport` Whether the model supports high effort level. - `Low BetaCapabilitySupport` Whether the model supports low effort level. - `Max BetaCapabilitySupport` Whether the model supports max effort level. - `Medium BetaCapabilitySupport` Whether the model supports medium effort level. - `Supported bool` Whether this capability is supported by the model. - `Xhigh BetaCapabilitySupport` Indicates whether a capability is supported. - `ImageInput BetaCapabilitySupport` Whether the model accepts image content blocks. - `PDFInput BetaCapabilitySupport` Whether the model accepts PDF content blocks. - `StructuredOutputs BetaCapabilitySupport` Whether the model supports structured output / JSON mode / strict tool schemas. - `Thinking BetaThinkingCapability` Thinking capability and supported type configurations. - `Supported bool` Whether this capability is supported by the model. - `Types BetaThinkingTypes` Supported thinking type configurations. - `Adaptive BetaCapabilitySupport` Whether the model supports thinking with type 'adaptive' (auto). - `Enabled BetaCapabilitySupport` Whether the model supports thinking with type 'enabled'. - `CreatedAt Time` RFC 3339 datetime string representing the time at which the model was released. May be set to an epoch value if the release date is unknown. - `DisplayName string` A human-readable name for the model. - `MaxInputTokens int64` Maximum input context window size in tokens for this model. - `MaxTokens int64` Maximum value for the `max_tokens` parameter when using this model. - `Type Model` Object type. For Models, this is always `"model"`. - `const ModelModel Model = "model"` ### Beta Thinking Capability - `type BetaThinkingCapability struct{…}` Thinking capability details. - `Supported bool` Whether this capability is supported by the model. - `Types BetaThinkingTypes` Supported thinking type configurations. - `Adaptive BetaCapabilitySupport` Whether the model supports thinking with type 'adaptive' (auto). - `Supported bool` Whether this capability is supported by the model. - `Enabled BetaCapabilitySupport` Whether the model supports thinking with type 'enabled'. ### Beta Thinking Types - `type BetaThinkingTypes struct{…}` Supported thinking type configurations. - `Adaptive BetaCapabilitySupport` Whether the model supports thinking with type 'adaptive' (auto). - `Supported bool` Whether this capability is supported by the model. - `Enabled BetaCapabilitySupport` Whether the model supports thinking with type 'enabled'.