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2026-07-13 12:58:18 +08:00

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Python

"""Dynamic A2UI tool: LLM-generated UI from conversation context.
This module provides the data preparation for a secondary LLM call that
generates v0.9 A2UI components. The actual LLM call is made by the
framework-specific wrapper (LangGraph, CrewAI, etc.) since each framework
has its own way of invoking LLMs.
"""
from __future__ import annotations
import json
import logging
from typing import Any, Optional
_logger = logging.getLogger(__name__)
CUSTOM_CATALOG_ID = "copilotkit://app-dashboard-catalog"
# The render_a2ui tool schema that the secondary LLM is bound to.
RENDER_A2UI_TOOL_SCHEMA = {
"name": "render_a2ui",
"description": (
"Render a dynamic A2UI v0.9 surface.\n\n"
"Args:\n"
" surfaceId: Unique surface identifier.\n"
' catalogId: The catalog ID (use "copilotkit://app-dashboard-catalog").\n'
" components: A2UI v0.9 component array (flat format). "
'The root component must have id "root".\n'
" data: Optional initial data model for the surface."
),
"parameters": {
"type": "object",
"properties": {
"surfaceId": {
"type": "string",
"description": "Unique surface identifier.",
},
"catalogId": {"type": "string", "description": "The catalog ID."},
"components": {
"type": "array",
"items": {"type": "object"},
"description": "A2UI v0.9 component array (flat format).",
},
"data": {
"type": "object",
"description": "Optional initial data model for the surface.",
},
},
"required": ["surfaceId", "catalogId", "components"],
},
}
def generate_a2ui_impl(
messages: list[dict[str, Any]],
context_entries: Optional[list[dict[str, Any]]] = None,
) -> dict[str, Any]:
"""Prepare inputs for a secondary LLM call that generates A2UI components.
Returns a dict with:
- system_prompt: The system prompt for the secondary LLM (built from context)
- tool_schema: The render_a2ui tool schema to bind to the LLM
- tool_choice: The tool name to force
- messages: The conversation messages to pass through
- catalog_id: The default catalog ID
The framework wrapper should:
1. Make an LLM call with these inputs
2. Extract the tool call args (surfaceId, catalogId, components, data)
3. Build a2ui_operations from the args and return them
"""
context_text = ""
if context_entries:
context_text = "\n\n".join(
entry.get("value", "")
for entry in context_entries
if isinstance(entry, dict) and entry.get("value")
)
return {
"system_prompt": context_text,
"tool_schema": RENDER_A2UI_TOOL_SCHEMA,
"tool_choice": "render_a2ui",
"messages": messages,
"catalog_id": CUSTOM_CATALOG_ID,
}
def _unstringify_json_fields(component: dict[str, Any]) -> dict[str, Any]:
"""Parse JSON-string fields back to Python values where the schema
expects structured data.
Gemini's structured-output sometimes emits `"data": "[{...}]"` (a JSON
string) instead of `"data": [...]` (the actual array) for fields
declared with an "any" type in the schema. The React A2UI renderer
expects real arrays/objects on data props — strings render as
"No data available" on charts. We round-trip those known structured
fields through json.loads so the renderer sees the right type.
Returns a new dict (does not mutate the input).
"""
out = dict(component)
for field in ("data", "value", "children"):
v = out.get(field)
if isinstance(v, str) and v.strip().startswith(("[", "{")):
try:
out[field] = json.loads(v)
except (ValueError, TypeError):
# Leave the raw string in place if it doesn't parse — the
# renderer will still receive a defined value rather than
# nothing, and downstream code can decide what to do.
pass
return out
def _sanitize_a2ui_components(raw: Any) -> list[dict[str, Any]]:
"""Drop entries that aren't dicts or are missing `id`/`component`,
then unstringify any JSON-as-string fields the model emitted.
Mirrors `langgraph-python/src/agents/_a2ui_utils.py:sanitize_a2ui_components`
with an added pass for Gemini's stringified `data` quirk.
"""
if not isinstance(raw, list):
return []
return [
_unstringify_json_fields(c)
for c in raw
if isinstance(c, dict) and c.get("id") and c.get("component")
]
def _has_root_component(components: list[dict[str, Any]]) -> bool:
"""True iff `components` contains an entry with `id == "root"`.
Mirrors `langgraph-python/src/agents/_a2ui_utils.py:has_root_component`.
"""
return any(c.get("id") == "root" for c in components)
def build_a2ui_operations_from_tool_call(args: dict[str, Any]) -> dict[str, Any]:
"""Build a2ui_operations dict from the secondary LLM's tool call args.
Call this after the framework wrapper extracts the tool call arguments.
Emits the v0.9 NESTED operation shape that
`@ag-ui/a2ui-middleware`'s `getOperationSurfaceId` and the React
A2UI renderer recognize:
{ "version": "v0.9", "createSurface": { surfaceId, catalogId } }
{ "version": "v0.9", "updateComponents": { surfaceId, components } }
{ "version": "v0.9", "updateDataModel": { surfaceId, path, value } }
The legacy flat shape (`{type: "create_surface", surfaceId, ...}`)
looked plausible but the middleware's matcher only walks the nested
`createSurface` / `updateComponents` / `updateDataModel` keys; when
those were absent it grouped every op under the fallback `"default"`
surface and the renderer never received the schema. Mirrors
`copilotkit.a2ui.create_surface` / `update_components` /
`update_data_model` from the langgraph-python north-star.
"""
surface_id = args.get("surfaceId", "dynamic-surface")
catalog_id = args.get("catalogId", CUSTOM_CATALOG_ID)
# Drop empty/malformed component entries before forwarding. Without
# this, the renderer errors on the first `undefined` id.
components = _sanitize_a2ui_components(args.get("components", []))
if not components:
_logger.warning(
"build_a2ui_operations_from_tool_call: all components were "
"dropped by sanitization (LLM emitted empty {} entries)"
)
elif not _has_root_component(components):
_logger.warning(
"build_a2ui_operations_from_tool_call: no component with id "
"'root' — the renderer will error with 'no root component'"
)
data = args.get("data")
ops: list[dict[str, Any]] = [
{
"version": "v0.9",
"createSurface": {"surfaceId": surface_id, "catalogId": catalog_id},
},
{
"version": "v0.9",
"updateComponents": {"surfaceId": surface_id, "components": components},
},
]
if data:
ops.append(
{
"version": "v0.9",
"updateDataModel": {
"surfaceId": surface_id,
"path": "/",
"value": data,
},
}
)
return {"a2ui_operations": ops}