{ "openapi": "3.1.0", "info": { "title": "SeedRouter Claude Sonnet 5.5", "version": "1.0.0", "description": "Sonnet 5.5 Messages contract and basic OpenAI-compatible endpoints. Known compatibility gaps include zero-output cache prewarming, stop sequences, and on-demand compaction. See the companion Markdown before relying on advanced options. Failed requests are not charged." }, "servers": [ { "url": "https://api.seedrouter.ai/v1" } ], "security": [ { "apiKeyHeader": [] }, { "bearerAuth": [] } ], "paths": { "/messages": { "post": { "summary": "Create a message (Anthropic Messages API)", "operationId": "createMessage", "requestBody": { "required": true, "content": { "application/json": { "schema": { "$ref": "#/components/schemas/MessagesRequest" } } } }, "responses": { "200": { "description": "The message, or a server-sent event stream when stream is true.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/Message" } }, "text/event-stream": { "schema": { "type": "string" } } } }, "400": { "description": "Public error in the Anthropic shape.", "content": { "application/json": { "schema": { "type": "object", "properties": { "type": { "const": "error" }, "error": { "type": "object", "properties": { "type": { "type": "string", "enum": [ "invalid_api_key", "permission_denied", "invalid_request_error", "insufficient_quota", "model_not_found", "task_not_found", "content_policy_violation", "generation_failed", "no_output", "delivery_failed", "service_unavailable", "rate_limited", "submission_unknown", "task_expired" ] }, "message": { "type": "string" } } } } } } } }, "401": { "description": "Public error in the Anthropic shape.", "content": { "application/json": { "schema": { "type": "object", "properties": { "type": { "const": "error" }, "error": { "type": "object", "properties": { "type": { "type": "string", "enum": [ "invalid_api_key", "permission_denied", "invalid_request_error", "insufficient_quota", "model_not_found", "task_not_found", "content_policy_violation", "generation_failed", "no_output", "delivery_failed", "service_unavailable", "rate_limited", "submission_unknown", "task_expired" ] }, "message": { "type": "string" } } } } } } } }, "402": { "description": "Public error in the Anthropic shape.", "content": { "application/json": { "schema": { "type": "object", "properties": { "type": { "const": "error" }, "error": { "type": "object", "properties": { "type": { "type": "string", "enum": [ "invalid_api_key", "permission_denied", "invalid_request_error", "insufficient_quota", "model_not_found", "task_not_found", "content_policy_violation", "generation_failed", "no_output", "delivery_failed", "service_unavailable", "rate_limited", "submission_unknown", "task_expired" ] }, "message": { "type": "string" } } } } } } } }, "429": { "description": "Public error in the Anthropic shape.", "content": { "application/json": { "schema": { "type": "object", "properties": { "type": { "const": "error" }, "error": { "type": "object", "properties": { "type": { "type": "string", "enum": [ "invalid_api_key", "permission_denied", "invalid_request_error", "insufficient_quota", "model_not_found", "task_not_found", "content_policy_violation", "generation_failed", "no_output", "delivery_failed", "service_unavailable", "rate_limited", "submission_unknown", "task_expired" ] }, "message": { "type": "string" } } } } } } } }, "503": { "description": "Public error in the Anthropic shape.", "content": { "application/json": { "schema": { "type": "object", "properties": { "type": { "const": "error" }, "error": { "type": "object", "properties": { "type": { "type": "string", "enum": [ "invalid_api_key", "permission_denied", "invalid_request_error", "insufficient_quota", "model_not_found", "task_not_found", "content_policy_violation", "generation_failed", "no_output", "delivery_failed", "service_unavailable", "rate_limited", "submission_unknown", "task_expired" ] }, "message": { "type": "string" } } } } } } } } }, "parameters": [ { "in": "header", "name": "anthropic-version", "required": true, "schema": { "type": "string", "default": "2023-06-01" } }, { "in": "header", "name": "anthropic-beta", "required": false, "schema": { "type": "string" }, "description": "Comma-separated beta identifiers required by the selected official features." } ] } }, "/chat/completions": { "post": { "summary": "Create a chat completion (OpenAI Chat Completions format)", "operationId": "createChatCompletion", "requestBody": { "required": true, "content": { "application/json": { "schema": { "type": "object", "required": [ "model" ], "additionalProperties": true, "description": "The OpenAI Chat Completions body; converted to this model.", "properties": { "model": { "type": "string", "enum": [ "claude-sonnet-5-5" ] } } } } } }, "responses": { "200": { "description": "A chat completion, or a stream." }, "400": { "description": "Public error; no infrastructure details.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } }, "401": { "description": "Public error; no infrastructure details.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } }, "429": { "description": "Public error; no infrastructure details.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } }, "503": { "description": "Public error; no infrastructure details.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } }, "/responses": { "post": { "summary": "Create a response (OpenAI Responses format)", "operationId": "createResponse", "requestBody": { "required": true, "content": { "application/json": { "schema": { "type": "object", "required": [ "model" ], "additionalProperties": true, "description": "The OpenAI Responses body; converted to this model.", "properties": { "model": { "type": "string", "enum": [ "claude-sonnet-5-5" ] } } } } } }, "responses": { "200": { "description": "A response object, or a stream." }, "400": { "description": "Public error; no infrastructure details.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } }, "401": { "description": "Public error; no infrastructure details.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } }, "429": { "description": "Public error; no infrastructure details.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } }, "503": { "description": "Public error; no infrastructure details.", "content": { "application/json": { "schema": { "$ref": "#/components/schemas/ErrorResponse" } } } } } } } }, "components": { "securitySchemes": { "bearerAuth": { "type": "http", "scheme": "bearer" }, "apiKeyHeader": { "type": "apiKey", "in": "header", "name": "x-api-key" } }, "schemas": { "MessagesRequest": { "type": "object", "required": [ "model", "max_tokens", "messages" ], "additionalProperties": true, "description": "Native Messages request. Model-specific restrictions apply. Keeping an optional field in a request does not establish that its behavior is implemented; see the compatibility report in the Markdown documentation.", "properties": { "model": { "type": "string", "enum": [ "claude-sonnet-5-5" ] }, "max_tokens": { "type": "integer", "minimum": 0, "maximum": 128000, "description": "Official range 0–128000, including thinking. Zero requests cache prewarming without generation; the 2026-10-01 compatibility test returned 400 for zero. The upper value was accepted but a full-length generation was not tested." }, "messages": { "type": "array", "items": { "type": "object", "required": [ "role", "content" ], "properties": { "role": { "type": "string", "enum": [ "user", "assistant", "system" ] }, "content": { "oneOf": [ { "type": "string" }, { "type": "array", "items": { "type": "object", "required": [ "type" ], "additionalProperties": true, "description": "A content block: text, image, document, tool_use, tool_result, thinking and the other official block types.", "properties": { "type": { "type": "string" } } } } ] }, "output_config": { "type": "object", "description": "Per-message effort requires mid-conversation-output-config-2026-07-01 on a system message. An effort-only message can appear anywhere; content-bearing system groups follow the placement rules.", "properties": { "effort": { "type": "string", "enum": [ "low", "medium", "high", "xhigh", "max" ] } } } } }, "minItems": 1, "maxItems": 100000, "description": "Conversation messages, including mid-conversation system messages under the official placement rules. Per-message effort requires mid-conversation-output-config-2026-07-01 on a system message; an effort-only message may appear anywhere." }, "system": { "oneOf": [ { "type": "string" }, { "type": "array", "items": { "type": "object", "required": [ "type", "text" ], "properties": { "type": { "const": "text" }, "text": { "type": "string" }, "cache_control": { "$ref": "#/components/schemas/CacheControl" } }, "additionalProperties": true } } ] }, "thinking": { "default": { "type": "adaptive" }, "oneOf": [ { "type": "object", "required": [ "type" ], "properties": { "type": { "const": "adaptive" }, "display": { "type": "string", "enum": [ "omitted", "summarized" ], "default": "omitted" }, "block_binding": { "type": "object", "description": "Official binding controls; requires thinking-binding-controls-2026-08-01.", "additionalProperties": true } }, "additionalProperties": false }, { "type": "object", "required": [ "type" ], "properties": { "type": { "const": "between_tools" } }, "additionalProperties": false } ], "description": "Adaptive by default. between_tools accepts no fields beyond type and requires effort low, medium or high. enabled, disabled and manual budgets are unsupported." }, "output_config": { "type": "object", "properties": { "effort": { "type": [ "string", "null" ], "enum": [ "low", "medium", "high", "xhigh", "max", null ], "default": "high" }, "format": { "oneOf": [ { "type": "object", "required": [ "type", "schema" ], "properties": { "type": { "const": "json_schema" }, "schema": { "type": "object", "additionalProperties": true } } }, { "type": "null" } ] } } }, "stop_sequences": { "type": "array", "items": { "type": "string" }, "description": "Official stopping strings. The current compatibility probe returned the matching string and following text; stopping behavior is not verified." }, "stream": { "type": "boolean", "default": false }, "temperature": { "type": [ "number", "null" ], "enum": [ 1, null ], "description": "Only the compatibility value 1 is accepted; omit sampling controls." }, "top_p": { "type": [ "number", "null" ], "minimum": 0.99, "maximum": 1 }, "tools": { "type": "array", "items": { "type": "object", "additionalProperties": true }, "description": "Official client/server tool definitions. Client tool name and input_schema are required. Native computer use requires computer_toolset_20260801. An accepted declaration does not verify server-tool execution." }, "tool_choice": { "oneOf": [ { "type": "object", "required": [ "type" ], "properties": { "type": { "const": "auto" }, "disable_parallel_tool_use": { "type": "boolean" } }, "additionalProperties": false }, { "type": "object", "required": [ "type" ], "properties": { "type": { "const": "none" } }, "additionalProperties": false } ], "default": { "type": "auto" }, "description": "Forced any/tool selection is unsupported." }, "metadata": { "type": "object", "properties": { "user_id": { "type": [ "string", "null" ], "maxLength": 512 } } }, "cache_control": { "$ref": "#/components/schemas/CacheControl" }, "container": { "oneOf": [ { "type": "string" }, { "type": "null" }, { "type": "object", "properties": { "id": { "type": [ "string", "null" ] }, "skills": { "type": [ "array", "null" ], "maxItems": 20, "items": { "type": "object", "required": [ "type", "skill_id" ], "properties": { "type": { "enum": [ "anthropic", "custom" ] }, "skill_id": { "type": "string", "minLength": 1, "maxLength": 64 }, "version": { "type": "string", "minLength": 1, "maxLength": 64 } }, "additionalProperties": true } } }, "additionalProperties": true } ] }, "context_management": { "anyOf": [ { "type": "object", "additionalProperties": true }, { "type": "null" } ] }, "mcp_servers": { "type": "array", "items": { "type": "object", "additionalProperties": true } }, "service_tier": { "type": "string", "enum": [ "auto", "standard_only" ], "default": "auto" }, "inference_geo": { "type": [ "string", "null" ], "description": "Official inference location. The test response reported not_available even when us was requested, so residency is not established." }, "diagnostics": { "oneOf": [ { "type": "object", "properties": { "previous_message_id": { "type": [ "string", "null" ], "maxLength": 256 } }, "additionalProperties": true }, { "type": "null" } ] }, "top_k": { "type": "null", "description": "Any non-null value is rejected for this model." }, "speed": { "enum": [ "standard", null ], "description": "Omit or use standard/null. Sonnet 5.5 does not support fast mode." }, "compaction": { "anyOf": [ { "type": "object", "required": [ "type" ], "properties": { "type": { "const": "summarize" } }, "additionalProperties": true, "description": "Requires compact-2026-09-04. Do not combine with context_management, stop_sequences or output_config.format. Signed compaction output did not pass the compatibility test." }, { "type": "null" } ] }, "fallbacks": { "description": "Beta: requires server-side-fallback-2026-07-01. Models must be distinct and differ from the primary model. Overrides follow each selected model contract. Cannot be combined with a non-null fallback_credit_token. End-to-end execution and billing have not been verified.", "anyOf": [ { "type": "null" }, { "const": "default" }, { "type": "array", "maxItems": 3, "items": { "type": "object", "required": [ "model" ], "additionalProperties": false, "properties": { "model": { "type": "string" }, "max_tokens": { "type": [ "integer", "null" ], "minimum": 0 }, "thinking": { "anyOf": [ { "type": "null" }, { "type": "object", "required": [ "type" ], "properties": { "type": { "enum": [ "adaptive", "enabled", "disabled", "between_tools" ] }, "budget_tokens": { "type": "integer", "minimum": 1024 }, "display": { "enum": [ "omitted", "summarized" ] }, "block_binding": { "type": "object", "additionalProperties": true } }, "description": "Use the selected fallback model thinking contract; between_tools allows only type, and enabled requires budget_tokens." } ] }, "output_config": { "anyOf": [ { "type": "null" }, { "type": "object", "properties": { "effort": { "type": [ "string", "null" ], "enum": [ "low", "medium", "high", "xhigh", "max", null ] }, "format": { "oneOf": [ { "type": "object", "required": [ "type", "schema" ], "properties": { "type": { "const": "json_schema" }, "schema": { "type": "object", "additionalProperties": true } } }, { "type": "null" } ] } } } ] }, "speed": { "enum": [ "standard", "fast", null ] } } } } ] }, "fallback_credit_token": { "description": "Opaque credit from a prior refusal. Redemption requires a fallback-credit beta or server-side-fallback-2026-07-01; object form requires fallback-credit-2026-07-01. A valid credit can authorize assistant-prefill replay. Token validity and credit redemption are not verified locally. Cannot be combined with non-null fallbacks.", "anyOf": [ { "type": "null" }, { "type": "string" }, { "type": "object", "required": [ "token" ], "additionalProperties": false, "properties": { "token": { "type": "string" }, "mode": { "enum": [ "strict", "best_effort" ], "default": "strict" } } } ] } }, "allOf": [ { "if": { "required": [ "thinking" ], "properties": { "thinking": { "required": [ "type" ], "properties": { "type": { "const": "between_tools" } } } } }, "then": { "properties": { "output_config": { "properties": { "effort": { "enum": [ "low", "medium", "high", null ] } } } } } }, { "if": { "required": [ "compaction" ], "properties": { "compaction": { "not": { "type": "null" } } } }, "then": { "not": { "anyOf": [ { "required": [ "context_management" ], "properties": { "context_management": { "not": { "type": "null" } } } }, { "required": [ "stop_sequences" ], "properties": { "stop_sequences": { "minItems": 1 } } } ] }, "properties": { "output_config": { "not": { "required": [ "format" ], "properties": { "format": { "not": { "type": "null" } } } } } } } }, { "not": { "required": [ "fallbacks", "fallback_credit_token" ], "properties": { "fallbacks": { "not": { "type": "null" } }, "fallback_credit_token": { "not": { "type": "null" } } } } } ] }, "Message": { "type": "object", "additionalProperties": true, "properties": { "id": { "type": "string" }, "type": { "const": "message" }, "role": { "const": "assistant" }, "model": { "type": "string" }, "content": { "type": "array", "items": { "type": "object", "required": [ "type" ], "additionalProperties": true, "description": "A content block: text, image, document, tool_use, tool_result, thinking and the other official block types.", "properties": { "type": { "type": "string" } } } }, "stop_reason": { "type": [ "string", "null" ] }, "stop_sequence": { "type": [ "string", "null" ] }, "usage": { "type": "object", "properties": { "input_tokens": { "type": "integer" }, "output_tokens": { "type": "integer" }, "cache_read_input_tokens": { "type": "integer" }, "cache_creation_input_tokens": { "type": "integer" }, "cache_creation": { "type": "object", "properties": { "ephemeral_5m_input_tokens": { "type": "integer" }, "ephemeral_1h_input_tokens": { "type": "integer" } } }, "inference_geo": { "type": "string" }, "service_tier": { "type": "string" }, "output_tokens_details": { "type": "object", "properties": { "thinking_tokens": { "type": "integer", "minimum": 0 } } }, "server_tool_use": { "type": "object", "additionalProperties": true }, "iterations": { "type": "array", "items": { "type": "object", "additionalProperties": true } }, "fallback_credit": { "type": [ "object", "null" ], "additionalProperties": true } } }, "container": { "type": [ "object", "null" ], "additionalProperties": true }, "diagnostics": { "type": [ "object", "null" ], "additionalProperties": true }, "context_management": { "type": [ "object", "null" ], "additionalProperties": true }, "stop_details": { "type": [ "object", "null" ], "additionalProperties": true }, "input_transformations": { "type": "array", "items": { "type": "object", "additionalProperties": true } } } }, "Error": { "type": "object", "required": [ "code", "message" ], "properties": { "code": { "type": "integer", "enum": [ 10001, 10002, 20001, 20002, 30001, 30002, 50001, 50002, 50003, 60001, 60002, 60003, 60004, 90001 ] }, "message": { "type": "string" } } }, "ErrorResponse": { "type": "object", "properties": { "error": { "$ref": "#/components/schemas/Error" } } } } } }