Zero Context Protocol
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SDK API

Reference index for the public Python SDK surface exported by `zcp`.

ZCP Python SDK API Reference

The Python distribution name is zero-context-protocol-sdk. The import path remains import zcp.

import zcp

This document lists the primary exported APIs and how they are grouped. For usage patterns, prefer the guides. Use this file when you already know the concept and need the symbol name.

Server Construction

Primary server-facing exports:

  • FastZCP
  • ZCPServerSession
  • create_asgi_app
  • ZCPASGIApp
  • run_mcp_stdio_server
  • run_mcp_stdio_server_sync

Registration APIs On FastZCP

Registration methods:

  • FastZCP.tool(...)
  • FastZCP.resource(...)
  • FastZCP.resource_template(...)
  • FastZCP.prompt(...)
  • FastZCP.completion(ref)
  • FastZCP.task(kind)

These methods define the public object model exposed through the runtime.

Client And Session APIs

Primary client-facing exports:

  • ZCPClientSession
  • ZCPSessionGroup
  • MCPGatewayClient
  • MCPGatewayServer

Important ZCPClientSession methods:

  • initialize(capabilities=None)
  • initialized()
  • ping()
  • list_tools(cursor=None, profile=None, groups=None, exclude_groups=None, stages=None)
  • call_tool(name, arguments, meta=None, task=None)
  • call_tool_as_task(name, arguments, ttl=60000, poll_interval=None, meta=None)
  • list_resources(cursor=None)
  • list_resource_templates(cursor=None)
  • read_resource(uri, arguments=None)
  • subscribe_resource(uri)
  • unsubscribe_resource(uri)
  • list_prompts(cursor=None)
  • get_prompt(name, arguments=None)
  • complete(ref, argument, value=None, context=None, context_arguments=None, method="completion/complete")
  • set_logging_level(level)
  • list_roots()
  • create_message(messages, **kwargs)
  • elicit(kind, prompt, **kwargs)
  • create_task(kind, input, task=None)
  • list_tasks(cursor=None)
  • get_task(task_id)
  • get_task_result(task_id)
  • cancel_task(task_id)

ZCPSessionGroup helpers:

  • list_tools(**kwargs)
  • list_resources()
  • list_prompts()

Tool exposure and native profiles:

  • ToolExposureConfig
  • SemanticWorkflowProfile

The most important built-in native profile is semantic-workflow. It is used with list_tools(profile="semantic-workflow") and returns only tools tagged with _meta.groups that include workflow when such tools exist.

For the dedicated conceptual page, see Semantic Workflow Profile.

Runtime And Schema Types

Selected exported runtime types:

  • ToolDefinition
  • ToolRegistry
  • PromptDescriptor
  • PromptArgument
  • ResourceDescriptor
  • ResourceTemplate
  • TaskDescriptor
  • TaskExecutionContext
  • SessionState
  • HandleStore
  • RuntimeExecutor
  • CanonicalValidator
  • ValidationFailure

Request and result models:

  • CompletionRequest
  • CompletionResult
  • SamplingRequest
  • SamplingResult
  • ElicitationRequest
  • ElicitationResult
  • InitializeParams
  • InitializeResult

Protocol and schema helpers:

  • CallRequest
  • CallResult
  • CallError
  • HandleRef
  • RegistryView
  • OpenAIStrictSchemaCompiler
  • encode_tool_output
  • decode_tool_output

Transport Helpers

Transport server helpers:

  • stdio_server
  • sse_server
  • streamable_http_server
  • websocket_server

Transport client helpers:

  • stdio_client
  • sse_client
  • streamable_http_client
  • websocket_client

These helpers are especially useful for tests and local orchestration code.

Profiles And Adapters

Exports for model/runtime adapter flows:

  • AgentLoop
  • MCPProfile
  • OpenAIAdapter
  • OpenAIResponsesAdapter
  • TurnResult
  • compile_openai_tools
  • format_call
  • format_registry
  • format_result
  • run_responses_turn
  • stream_responses_turn
  • submit_tool_results

Auth And Capability Types

Auth-related exports:

  • AuthContext
  • AuthProfile
  • OAuthConfig
  • OAuthProvider
  • OAuthClient
  • AuthorizationCode
  • AccessToken
  • RefreshToken
  • InMemoryOAuthProvider
  • SQLiteOAuthProvider
  • BearerAuthConfig

Capability-related exports:

  • Capabilities
  • PROTOCOL_VERSION
  • ProgressToken

Server Configuration Types

Configuration exports:

  • ZCPServerConfig
  • HTTPConfig
  • SSEConfig
  • StreamableHTTPConfig
  • WebSocketConfig
  • RateLimitConfig

These determine transport routes, auth behavior, replay behavior, websocket availability, and coarse request limits.

Notes

  • MCP compatibility is exposed on top of the same runtime core.
  • Native ZCP remains the optimization path for token-sensitive workloads.
  • Use server_guide.md and client_guide.md for workflow-level explanation.