ag-ui-a2ui-toolkit

Framework-agnostic helpers for building A2UI subagent tools.

Each per-framework adapter (LangGraph, ADK, Mastra, …) composes these helpers with its own framework-specific glue: tool decorator, runtime accessor, model binding + invoke. Nothing in this package depends on any agent framework.

Surface

• Constants: A2UI_OPERATIONS_KEY, BASIC_CATALOG_ID, DEFAULT_SURFACE_ID, GENERATE_A2UI_TOOL_NAME, GENERATE_A2UI_TOOL_DESCRIPTION, GENERATE_A2UI_ARG_DESCRIPTIONS
• Op builders: create_surface, update_components, update_data_model
• RENDER_A2UI_TOOL_DEF — JSON schema for the inner structured-output tool
• State + history helpers: build_context_prompt, find_prior_surface
• Prompt composer: build_subagent_prompt
• High-level orchestration: prepare_a2ui_request, build_a2ui_envelope
• Output wrappers: assemble_ops, wrap_as_operations_envelope, wrap_error_envelope

See also

The TypeScript counterpart lives in @ag-ui/a2ui-toolkit and exposes the same surface in camelCase.