chore: initial public snapshot for github upload
This commit is contained in:
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# A2A Protocol Guardrail Translation Handler
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Handler for processing A2A (Agent-to-Agent) Protocol messages with guardrails.
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## Overview
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This handler processes A2A JSON-RPC 2.0 input/output by:
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1. Extracting text from message parts (`kind: "text"`)
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2. Applying guardrails to text content
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3. Mapping guardrailed text back to original structure
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## A2A Protocol Format
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### Input Format (JSON-RPC 2.0)
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```json
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{
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"jsonrpc": "2.0",
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"id": "request-id",
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"method": "message/send",
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"params": {
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"message": {
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"kind": "message",
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"messageId": "...",
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"role": "user",
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"parts": [
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{"kind": "text", "text": "Hello, my SSN is 123-45-6789"}
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]
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},
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"metadata": {
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"guardrails": ["block-ssn"]
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}
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}
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}
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```
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### Output Formats
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The handler supports multiple A2A response formats:
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**Direct message:**
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```json
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{
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"result": {
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"kind": "message",
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"parts": [{"kind": "text", "text": "Response text"}]
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}
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}
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```
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**Nested message:**
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```json
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{
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"result": {
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"message": {
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"parts": [{"kind": "text", "text": "Response text"}]
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}
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}
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}
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```
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**Task with artifacts:**
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```json
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{
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"result": {
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"kind": "task",
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"artifacts": [
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{"parts": [{"kind": "text", "text": "Artifact text"}]}
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]
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}
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}
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```
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**Task with status message:**
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```json
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{
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"result": {
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"kind": "task",
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"status": {
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"message": {
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"parts": [{"kind": "text", "text": "Status message"}]
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}
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}
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}
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}
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```
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**Streaming artifact-update:**
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```json
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{
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"result": {
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"kind": "artifact-update",
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"artifact": {
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"parts": [{"kind": "text", "text": "Streaming text"}]
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}
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}
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}
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```
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## Usage
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The handler is automatically discovered and applied when guardrails are used with A2A endpoints.
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### Via LiteLLM Proxy
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```bash
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curl -X POST 'http://localhost:4000/a2a/my-agent' \
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-H 'Content-Type: application/json' \
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-H 'Authorization: Bearer your-api-key' \
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-d '{
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"jsonrpc": "2.0",
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"id": "1",
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"method": "message/send",
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"params": {
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"message": {
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"kind": "message",
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"messageId": "msg-1",
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"role": "user",
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"parts": [{"kind": "text", "text": "Hello, my SSN is 123-45-6789"}]
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},
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"metadata": {
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"guardrails": ["block-ssn"]
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}
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}
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}'
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```
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### Specifying Guardrails
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Guardrails can be specified in the A2A request via the `metadata.guardrails` field:
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```json
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{
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"params": {
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"message": {...},
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"metadata": {
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"guardrails": ["block-ssn", "pii-filter"]
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}
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}
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}
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```
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## Extension
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Override these methods to customize behavior:
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- `_extract_texts_from_result()`: Custom text extraction from A2A responses
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- `_extract_texts_from_parts()`: Custom text extraction from message parts
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- `_apply_text_to_path()`: Custom application of guardrailed text
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## Call Types
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This handler is registered for:
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- `CallTypes.send_message`: Synchronous A2A message sending
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- `CallTypes.asend_message`: Asynchronous A2A message sending
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"""A2A Protocol handler for Unified Guardrails."""
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from litellm.llms.a2a.chat.guardrail_translation.handler import A2AGuardrailHandler
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from litellm.types.utils import CallTypes
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guardrail_translation_mappings = {
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CallTypes.send_message: A2AGuardrailHandler,
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CallTypes.asend_message: A2AGuardrailHandler,
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}
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__all__ = ["guardrail_translation_mappings"]
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@@ -0,0 +1,428 @@
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"""
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A2A Protocol Handler for Unified Guardrails
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This module provides guardrail translation support for A2A (Agent-to-Agent) Protocol.
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It handles both JSON-RPC 2.0 input requests and output responses, extracting text
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from message parts and applying guardrails.
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A2A Protocol Format:
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- Input: JSON-RPC 2.0 with params.message.parts containing text parts
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- Output: JSON-RPC 2.0 with result containing message/artifact parts
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"""
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import json
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from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple, Union
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from litellm._logging import verbose_proxy_logger
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from litellm.llms.base_llm.guardrail_translation.base_translation import BaseTranslation
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from litellm.types.utils import GenericGuardrailAPIInputs
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if TYPE_CHECKING:
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from litellm.integrations.custom_guardrail import CustomGuardrail
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from litellm.litellm_core_utils.litellm_logging import Logging as LiteLLMLoggingObj
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from litellm.proxy._types import UserAPIKeyAuth
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class A2AGuardrailHandler(BaseTranslation):
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"""
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Handler for processing A2A Protocol messages with guardrails.
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This class provides methods to:
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1. Process input messages (pre-call hook) - extracts text from A2A message parts
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2. Process output responses (post-call hook) - extracts text from A2A response parts
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A2A Message Format:
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- Input: params.message.parts[].text (where kind == "text")
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- Output: result.message.parts[].text or result.artifacts[].parts[].text
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"""
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async def process_input_messages(
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self,
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data: dict,
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guardrail_to_apply: "CustomGuardrail",
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litellm_logging_obj: Optional["LiteLLMLoggingObj"] = None,
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) -> Any:
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"""
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Process A2A input messages by applying guardrails to text content.
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Extracts text from A2A message parts and applies guardrails.
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Args:
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data: The A2A JSON-RPC 2.0 request data
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guardrail_to_apply: The guardrail instance to apply
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litellm_logging_obj: Optional logging object
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Returns:
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Modified data with guardrails applied to text content
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"""
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# A2A request format: { "params": { "message": { "parts": [...] } } }
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params = data.get("params", {})
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message = params.get("message", {})
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parts = message.get("parts", [])
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if not parts:
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verbose_proxy_logger.debug("A2A: No parts in message, skipping guardrail")
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return data
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texts_to_check: List[str] = []
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text_part_indices: List[int] = [] # Track which parts contain text
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# Step 1: Extract text from all text parts
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for part_idx, part in enumerate(parts):
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if part.get("kind") == "text":
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text = part.get("text", "")
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if text:
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texts_to_check.append(text)
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text_part_indices.append(part_idx)
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# Step 2: Apply guardrail to all texts in batch
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if texts_to_check:
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inputs = GenericGuardrailAPIInputs(texts=texts_to_check)
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# Pass the structured A2A message to guardrails
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inputs["structured_messages"] = [message]
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# Include agent model info if available
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model = data.get("model")
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if model:
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inputs["model"] = model
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guardrailed_inputs = await guardrail_to_apply.apply_guardrail(
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inputs=inputs,
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request_data=data,
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input_type="request",
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logging_obj=litellm_logging_obj,
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)
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guardrailed_texts = guardrailed_inputs.get("texts", [])
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# Step 3: Apply guardrailed text back to original parts
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if guardrailed_texts and len(guardrailed_texts) == len(text_part_indices):
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for task_idx, part_idx in enumerate(text_part_indices):
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parts[part_idx]["text"] = guardrailed_texts[task_idx]
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verbose_proxy_logger.debug("A2A: Processed input message: %s", message)
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return data
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async def process_output_response(
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self,
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response: Any,
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guardrail_to_apply: "CustomGuardrail",
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litellm_logging_obj: Optional["LiteLLMLoggingObj"] = None,
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user_api_key_dict: Optional["UserAPIKeyAuth"] = None,
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) -> Any:
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"""
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Process A2A output response by applying guardrails to text content.
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Handles multiple A2A response formats:
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- Direct message: {"result": {"kind": "message", "parts": [...]}}
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- Nested message: {"result": {"message": {"parts": [...]}}}
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- Task with artifacts: {"result": {"kind": "task", "artifacts": [{"parts": [...]}]}}
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- Task with status message: {"result": {"kind": "task", "status": {"message": {"parts": [...]}}}}
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Args:
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response: A2A JSON-RPC 2.0 response dict or object
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guardrail_to_apply: The guardrail instance to apply
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litellm_logging_obj: Optional logging object
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user_api_key_dict: User API key metadata
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Returns:
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Modified response with guardrails applied to text content
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"""
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# Handle both dict and Pydantic model responses
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if hasattr(response, "model_dump"):
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response_dict = response.model_dump()
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is_pydantic = True
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elif isinstance(response, dict):
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response_dict = response
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is_pydantic = False
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else:
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verbose_proxy_logger.warning(
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"A2A: Unknown response type %s, skipping guardrail", type(response)
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)
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return response
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result = response_dict.get("result", {})
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if not result or not isinstance(result, dict):
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verbose_proxy_logger.debug("A2A: No result in response, skipping guardrail")
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return response
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# Find all text-containing parts in the response
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texts_to_check: List[str] = []
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# Each mapping is (path_to_parts_list, part_index)
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# path_to_parts_list is a tuple of keys to navigate to the parts list
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task_mappings: List[Tuple[Tuple[str, ...], int]] = []
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# Extract texts from all possible locations
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self._extract_texts_from_result(
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result=result,
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texts_to_check=texts_to_check,
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task_mappings=task_mappings,
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)
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if not texts_to_check:
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verbose_proxy_logger.debug("A2A: No text content in response")
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return response
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# Step 2: Apply guardrail to all texts in batch
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# Create a request_data dict with response info and user API key metadata
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request_data: dict = {"response": response_dict}
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# Add user API key metadata with prefixed keys
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user_metadata = self.transform_user_api_key_dict_to_metadata(user_api_key_dict)
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if user_metadata:
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request_data["litellm_metadata"] = user_metadata
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inputs = GenericGuardrailAPIInputs(texts=texts_to_check)
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guardrailed_inputs = await guardrail_to_apply.apply_guardrail(
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inputs=inputs,
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request_data=request_data,
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input_type="response",
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logging_obj=litellm_logging_obj,
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)
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guardrailed_texts = guardrailed_inputs.get("texts", [])
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# Step 3: Apply guardrailed text back to original response
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if guardrailed_texts and len(guardrailed_texts) == len(task_mappings):
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for task_idx, (path, part_idx) in enumerate(task_mappings):
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self._apply_text_to_path(
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result=result,
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path=path,
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part_idx=part_idx,
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text=guardrailed_texts[task_idx],
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)
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verbose_proxy_logger.debug("A2A: Processed output response")
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# Update the original response
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if is_pydantic:
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# For Pydantic models, we need to update the underlying dict
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# and the model will reflect the changes
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response_dict["result"] = result
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return response
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else:
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response["result"] = result
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return response
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async def process_output_streaming_response(
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self,
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responses_so_far: List[Any],
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guardrail_to_apply: "CustomGuardrail",
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litellm_logging_obj: Optional["LiteLLMLoggingObj"] = None,
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user_api_key_dict: Optional["UserAPIKeyAuth"] = None,
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) -> List[Any]:
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"""
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Process A2A streaming output by applying guardrails to accumulated text.
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responses_so_far can be a list of JSON-RPC 2.0 objects (dict or NDJSON str), e.g.:
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- task with history, status-update, artifact-update (with result.artifact.parts),
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- then status-update (final). Text is extracted from result.artifact.parts,
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result.message.parts, result.parts, etc., concatenated in order, guardrailed once,
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then the combined guardrailed text is written into the first chunk that had text
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and all other text parts in other chunks are cleared (in-place).
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"""
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from litellm.llms.a2a.common_utils import extract_text_from_a2a_response
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# Parse each item; keep alignment with responses_so_far (None where unparseable)
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parsed: List[Optional[Dict[str, Any]]] = [None] * len(responses_so_far)
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for i, item in enumerate(responses_so_far):
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if isinstance(item, dict):
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obj = item
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||||
elif isinstance(item, str):
|
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try:
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||||
obj = json.loads(item.strip())
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except (json.JSONDecodeError, TypeError):
|
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continue
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||||
else:
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continue
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if isinstance(obj.get("result"), dict):
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parsed[i] = obj
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||||
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||||
valid_parsed = [(i, obj) for i, obj in enumerate(parsed) if obj is not None]
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if not valid_parsed:
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return responses_so_far
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||||
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||||
# Collect text from each chunk in order (by original index in responses_so_far)
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||||
text_parts: List[str] = []
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chunk_indices_with_text: List[int] = [] # indices into valid_parsed
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||||
for idx, (orig_i, obj) in enumerate(valid_parsed):
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||||
t = extract_text_from_a2a_response(obj)
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if t:
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||||
text_parts.append(t)
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||||
chunk_indices_with_text.append(orig_i)
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||||
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||||
combined_text = "".join(text_parts)
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||||
if not combined_text:
|
||||
return responses_so_far
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||||
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||||
request_data: dict = {"responses_so_far": responses_so_far}
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||||
user_metadata = self.transform_user_api_key_dict_to_metadata(user_api_key_dict)
|
||||
if user_metadata:
|
||||
request_data["litellm_metadata"] = user_metadata
|
||||
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||||
inputs = GenericGuardrailAPIInputs(texts=[combined_text])
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||||
guardrailed_inputs = await guardrail_to_apply.apply_guardrail(
|
||||
inputs=inputs,
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||||
request_data=request_data,
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||||
input_type="response",
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||||
logging_obj=litellm_logging_obj,
|
||||
)
|
||||
guardrailed_texts = guardrailed_inputs.get("texts", [])
|
||||
if not guardrailed_texts:
|
||||
return responses_so_far
|
||||
guardrailed_text = guardrailed_texts[0]
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||||
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||||
# Find first chunk (by original index) that has text; put full guardrailed text there and clear rest
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||||
first_chunk_with_text: Optional[int] = (
|
||||
chunk_indices_with_text[0] if chunk_indices_with_text else None
|
||||
)
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||||
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||||
for orig_i, obj in valid_parsed:
|
||||
result = obj.get("result", {})
|
||||
if not isinstance(result, dict):
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||||
continue
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||||
texts_in_chunk: List[str] = []
|
||||
mappings: List[Tuple[Tuple[str, ...], int]] = []
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||||
self._extract_texts_from_result(
|
||||
result=result,
|
||||
texts_to_check=texts_in_chunk,
|
||||
task_mappings=mappings,
|
||||
)
|
||||
if not mappings:
|
||||
continue
|
||||
if orig_i == first_chunk_with_text:
|
||||
# Put full guardrailed text in first text part; clear others
|
||||
for task_idx, (path, part_idx) in enumerate(mappings):
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||||
text = guardrailed_text if task_idx == 0 else ""
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||||
self._apply_text_to_path(
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||||
result=result,
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||||
path=path,
|
||||
part_idx=part_idx,
|
||||
text=text,
|
||||
)
|
||||
else:
|
||||
for path, part_idx in mappings:
|
||||
self._apply_text_to_path(
|
||||
result=result,
|
||||
path=path,
|
||||
part_idx=part_idx,
|
||||
text="",
|
||||
)
|
||||
|
||||
# Write back to responses_so_far where we had NDJSON strings
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||||
for i, item in enumerate(responses_so_far):
|
||||
if isinstance(item, str) and parsed[i] is not None:
|
||||
responses_so_far[i] = json.dumps(parsed[i]) + "\n"
|
||||
|
||||
return responses_so_far
|
||||
|
||||
def _extract_texts_from_result(
|
||||
self,
|
||||
result: Dict[str, Any],
|
||||
texts_to_check: List[str],
|
||||
task_mappings: List[Tuple[Tuple[str, ...], int]],
|
||||
) -> None:
|
||||
"""
|
||||
Extract text from all possible locations in an A2A result.
|
||||
|
||||
Handles multiple response formats:
|
||||
1. Direct message with parts: {"parts": [...]}
|
||||
2. Nested message: {"message": {"parts": [...]}}
|
||||
3. Task with artifacts: {"artifacts": [{"parts": [...]}]}
|
||||
4. Task with status message: {"status": {"message": {"parts": [...]}}}
|
||||
5. Streaming artifact-update: {"artifact": {"parts": [...]}}
|
||||
"""
|
||||
# Case 1: Direct parts in result (direct message)
|
||||
if "parts" in result:
|
||||
self._extract_texts_from_parts(
|
||||
parts=result["parts"],
|
||||
path=("parts",),
|
||||
texts_to_check=texts_to_check,
|
||||
task_mappings=task_mappings,
|
||||
)
|
||||
|
||||
# Case 2: Nested message
|
||||
message = result.get("message")
|
||||
if message and isinstance(message, dict) and "parts" in message:
|
||||
self._extract_texts_from_parts(
|
||||
parts=message["parts"],
|
||||
path=("message", "parts"),
|
||||
texts_to_check=texts_to_check,
|
||||
task_mappings=task_mappings,
|
||||
)
|
||||
|
||||
# Case 3: Streaming artifact-update (singular artifact)
|
||||
artifact = result.get("artifact")
|
||||
if artifact and isinstance(artifact, dict) and "parts" in artifact:
|
||||
self._extract_texts_from_parts(
|
||||
parts=artifact["parts"],
|
||||
path=("artifact", "parts"),
|
||||
texts_to_check=texts_to_check,
|
||||
task_mappings=task_mappings,
|
||||
)
|
||||
|
||||
# Case 4: Task with status message
|
||||
status = result.get("status", {})
|
||||
if isinstance(status, dict):
|
||||
status_message = status.get("message")
|
||||
if (
|
||||
status_message
|
||||
and isinstance(status_message, dict)
|
||||
and "parts" in status_message
|
||||
):
|
||||
self._extract_texts_from_parts(
|
||||
parts=status_message["parts"],
|
||||
path=("status", "message", "parts"),
|
||||
texts_to_check=texts_to_check,
|
||||
task_mappings=task_mappings,
|
||||
)
|
||||
|
||||
# Case 5: Task with artifacts (plural, array)
|
||||
artifacts = result.get("artifacts", [])
|
||||
if artifacts and isinstance(artifacts, list):
|
||||
for artifact_idx, art in enumerate(artifacts):
|
||||
if isinstance(art, dict) and "parts" in art:
|
||||
self._extract_texts_from_parts(
|
||||
parts=art["parts"],
|
||||
path=("artifacts", str(artifact_idx), "parts"),
|
||||
texts_to_check=texts_to_check,
|
||||
task_mappings=task_mappings,
|
||||
)
|
||||
|
||||
def _extract_texts_from_parts(
|
||||
self,
|
||||
parts: List[Dict[str, Any]],
|
||||
path: Tuple[str, ...],
|
||||
texts_to_check: List[str],
|
||||
task_mappings: List[Tuple[Tuple[str, ...], int]],
|
||||
) -> None:
|
||||
"""Extract text from message parts."""
|
||||
for part_idx, part in enumerate(parts):
|
||||
if part.get("kind") == "text":
|
||||
text = part.get("text", "")
|
||||
if text:
|
||||
texts_to_check.append(text)
|
||||
task_mappings.append((path, part_idx))
|
||||
|
||||
def _apply_text_to_path(
|
||||
self,
|
||||
result: Dict[Union[str, int], Any],
|
||||
path: Tuple[str, ...],
|
||||
part_idx: int,
|
||||
text: str,
|
||||
) -> None:
|
||||
"""Apply guardrailed text back to the specified path in the result."""
|
||||
# Navigate to the parts list
|
||||
current = result
|
||||
for key in path:
|
||||
if key.isdigit():
|
||||
# Array index
|
||||
current = current[int(key)]
|
||||
else:
|
||||
current = current[key]
|
||||
|
||||
# Update the text in the part
|
||||
current[part_idx]["text"] = text
|
||||
Reference in New Issue
Block a user