II.
ModelTransportProtocol overview
Reference · livemodel-transport:anthropic-messages
Anthropic Messages overview
Inspect the raw attributes, linked wiki pages, and inbound or outbound graph edges for model-transport:anthropic-messages.
Attributes
displayName
Anthropic Messages
vendor
Anthropic
specUrl
streamingFraming
sse
toolUseSchema
Tool calls appear as `tool_use` content blocks with `id`, `name`, and
`input`; results are returned as `tool_result` blocks referencing the
same `id`.
thinkingChannel
content-block
cacheControl
explicit
firstSpecVersion
2023-07-12
currentSpecVersion
2025-04-01
status
standard
requestBodyShape
POST /v1/messages
JSON body (top-level fields):
- `model` (required, string)
- `messages` (required, array of `{role: "user"|"assistant", content: string|ContentBlock[]}`)
- `system` (optional, string or array of content blocks)
- `max_tokens` (required, int)
- `tools` (optional, array of tool definitions `{name, description, input_schema}`)
- `tool_choice` (optional, `{type: "auto"|"any"|"tool", name?}`)
- `temperature`, `top_p`, `top_k`, `stop_sequences` (optional)
- `stream` (optional, bool)
- `thinking` (optional, `{type: "enabled", budget_tokens}` for extended thinking)
- `metadata` (optional, `{user_id?}`)
responseBodyShape
Non-streaming response (HTTP 200 application/json):
{
"id": "msg_...",
"type": "message",
"role": "assistant",
"model": "...",
"content": [ ContentBlock, ... ],
"stop_reason": "end_turn"|"max_tokens"|"stop_sequence"|"tool_use",
"stop_sequence": null|string,
"usage": {
"input_tokens": int,
"output_tokens": int,
"cache_creation_input_tokens"?: int,
"cache_read_input_tokens"?: int
}
}
streamingEventTypes
- message_start
- content_block_start
- content_block_delta
- content_block_stop
- message_delta
- message_stop
- ping
- error
toolCallWireFormat
A `tool_use` content block in `message.content`:
{ "type": "tool_use", "id": "toolu_...", "name": "<tool_name>", "input": { ... } }
`id` is the call correlation handle echoed back on the matching tool result.
toolResultWireFormat
A `tool_result` content block in a subsequent user-role message:
{ "type": "tool_result",
"tool_use_id": "toolu_...",
"content": string | ContentBlock[],
"is_error"?: bool }
errorEnvelope
Non-2xx response, `application/json`:
{ "type": "error",
"error": { "type": "invalid_request_error"|"authentication_error"|"permission_error"|"not_found_error"|"rate_limit_error"|"api_error"|"overloaded_error"|"request_too_large", "message": string } }
HTTP status: 400/401/403/404/413/429/500/529 according to `error.type`.
cacheControlWireFormat
Per-content-block annotation:
{ "type": "text", "text": "...", "cache_control": { "type": "ephemeral", "ttl"?: "5m"|"1h" } }
Up to four cache breakpoints per request. Applies to system, messages, and tools.
rateLimitSignaling
Response headers on every request:
- `anthropic-ratelimit-requests-limit`, `anthropic-ratelimit-requests-remaining`,
`anthropic-ratelimit-requests-reset`
- `anthropic-ratelimit-tokens-limit`, `anthropic-ratelimit-tokens-remaining`,
`anthropic-ratelimit-tokens-reset`
- `anthropic-ratelimit-input-tokens-*`, `anthropic-ratelimit-output-tokens-*`
On HTTP 429: `retry-after` header (seconds).
reasoningWireFormat
A `thinking` content block:
{ "type": "thinking", "thinking": "<text>", "signature": "<opaque>" }
Redacted variant when content is filtered server-side:
{ "type": "redacted_thinking", "data": "<opaque>" }
Both must be echoed back verbatim (preserving signatures) on multi-turn
tool-use loops or extended-thinking continuations.
authHeaderFormat
`x-api-key: <ANTHROPIC_API_KEY>`
(Bedrock / Vertex use their respective IAM/OAuth flows instead.)
versioningHeader
Mandatory: `anthropic-version: 2023-06-01`
Optional opt-ins: `anthropic-beta: <feature>[,<feature>...]`
Outgoing edges
bridged_by1
- transport-proxy:adapters-proxy·TransportProxyAgent-Adapter Proxy
realizes1
- layer:3-transport·LayerTransport
served_by2
- provider:anthropic·ModelProviderProductAnthropic
- provider:aws-bedrock·Provider
spoken_by1
- model:claude-opus-4-7@current·ModelVersionClaude 4.7 Opus
Incoming edges
bridges1
- transport-proxy:adapters-proxy·TransportProxyAgent-Adapter Proxy
speaks28
- agent-core-impl:a5c.core@current·AgentCoreImpla5c Unified Core (current) — unified agent loop
- agent-core-impl:claude-agent-sdk.core@current·AgentCoreImplClaude Agent SDK Core (current)
- agent-core-impl:claude-code.core@1.x·AgentCoreImplClaude Code Core (1.x)
- agent-core-impl:claude-code-remote-control.core@current·AgentCoreImplClaude Code Remote Control Core (current)
- agent-core-impl:cursor.core@current·AgentCoreImplCursor Core (current)
- agent-core-impl:hermes.core@current·AgentCoreImplHermes Core (current)
- agent-core-impl:langgraph.core@current·AgentCoreImplLangGraph Graph Core (current)
- agent-core-impl:omp.core@current·AgentCoreImplOMP Core (current)
- agent-core-impl:openclaw.core@current·AgentCoreImplOpenClaw Core (current)
- agent-core-impl:opencode.core@1.x·AgentCoreImplOpenCode Core (1.x)
- agent-core-impl:paperclip.core@current·AgentCoreImplPaperclip Core (current)
- agent-core-impl:pi.core@current·AgentCoreImplPi Core (current)
- agent-core-impl:pikiclaw.core@current·AgentCoreImplPikiClaw Core (current)
- agent-core-impl:vibe-kanban.core@current·AgentCoreImplVibe Kanban Core (current)
- model:claude-fable-5@current·ModelVersionClaude Fable 5
- model:claude-haiku-4-5@current·ModelVersionClaude 4.5 Haiku
- model:claude-mythos-5@current·ModelVersionClaude Mythos 5
- model:claude-mythos-preview@current·ModelVersionClaude Mythos Preview
- model:claude-opus-3@current·ModelVersionClaude 3 Opus
- model:claude-opus-4-5@current·ModelVersionClaude 4.5 Opus
- model:claude-opus-4-6@current·ModelVersionClaude 4.6 Opus
- model:claude-opus-4-7@current·ModelVersionClaude 4.7 Opus
- model:claude-sonnet-3-5@current·ModelVersionClaude 3.5 Sonnet
- model:claude-sonnet-4-5@current·ModelVersionClaude 4.5 Sonnet
- model:claude-sonnet-4-6@current·ModelVersionClaude 4.6 Sonnet
- model:deepseek-v4-flash@current·ModelVersionDeepSeek V4 Flash
- model:deepseek-v4-pro@current·ModelVersionDeepSeek V4 Pro
- model:claude-opus-4-8@current·ModelVersionClaude Opus 4.8