GET

/v1/schemas/anthropic/chat/v1%2Fmessages%3Fbeta%3Dtrue

kind inputactivity chathash 906b2fa6extracted Jul 25, 2026version currentsource upstream spec ↗

Request body

25 properties · 3 required · 142 $defs
propertytypedescriptionconstraints
model*stringThe model that will complete your prompt.17 known values
messages*BetaInputMessage[]Input messages.
max_tokens*integerThe maximum number of tokens to generate before stopping.n ≥ 0
cache_controlBetaCacheControlEphemeralTop-level cache control automatically applies a cache_control marker to the last cacheable block in the request.nullable
containerContainerParams | stringContainer identifier for reuse across requests.nullable
context_managementBetaContextManagementConfigContext management configuration. This allows you to control how Claude manages context across multiple requests, such as whether to clear function results or not.nullable
diagnosticsBetaDiagnosticsParamRequest-level diagnostics. Currently carries the previous response id for prompt-cache divergence reporting.nullable
fallback_credit_tokenstring | FallbackCreditTokenParamThe `fallback_credit_token` from a prior refusal's `stop_details`.nullable
fallbacksBetaFallbackConfigV2[] | "default"Opt-in server-side retry on one or more substitute models when the requested model declines for policy reasons. Tried in order: if the first entry also declines, the second is tried, and so on. The string "default" requests the requested model's server-defined…nullable
inference_geostringSpecifies the geographic region for inference processing. If not specified, the workspace's `default_inference_geo` is used.nullable
mcp_serversBetaRequestMCPServerURLDefinition[]MCP servers to be utilized in this requestitems ≤ 20
metadataBetaMetadataAn object describing metadata about the request.
output_configBetaOutputConfigConfiguration options for the model's output, such as the output format.
output_formatBetaJsonOutputFormatDeprecated: Use `output_config.format` instead. See [structured outputs](https://platform.claude.com/docs/en/build-with-claude/structured-outputs) A schema to specify Claude's output format in responses. This parameter will be removed in a future release.nullable · deprecated
service_tierenumDetermines whether to use priority capacity (if available) or standard capacity for this request.auto | standard_only
speedenumInference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.standard | fast · nullable
stop_sequencesstring[]Custom text sequences that will cause the model to stop generating.
streambooleanWhether to incrementally stream the response using server-sent events.
systemstring | BetaRequestTextBlock[]System prompt.
temperaturenumberAmount of randomness injected into the response.0 ≤ n ≤ 1 · deprecated
thinkingThinkingConfigEnabled | ThinkingConfigDi…Configuration for enabling Claude's extended thinking.
tool_choiceToolChoiceAuto | ToolChoiceAny | ToolCho…How the model should use the provided tools. The model can use a specific tool, any available tool, decide by itself, or not use tools at all.
toolsBetaTool | BetaBashTool_20241022 | BetaBashTool_20250124[]Definitions of tools that the model may use.
top_kintegerOnly sample from the top K options for each subsequent token.n ≥ 0 · deprecated
top_pnumberUse nucleus sampling.0 ≤ n ≤ 1 · deprecated

Validate a payload

before you spend tokens
shell
$ curl -X POST https://modelschemas.com/v1/validate \
    -d '{"provider":"anthropic","endpointId":"v1/messages?beta=true","payload":{…}}'
→ {"valid": false, "errors": [{"path": "#", "keyword": "required", …}]}