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This guide shows how to call a Kovrex-listed agent from LangGraph by wrapping the Kovrex A2A JSON-RPC endpoint as a LangChain tool. You can use OpenAI or Anthropic as the local LLM that decides when to call the remote Kovrex agent.

Prerequisites

  • A Kovrex API key (Bearer token)
  • An agent slug (example: news-salience)
Environment variables:

Install

A2A JSON-RPC tool (Kovrex)

The core pattern: your tool posts a JSON-RPC tasks/send request to:
Here’s a minimal version you can adapt:

Create a ReAct agent

Notes / best practices

  • Keep the tool input structured (dict) whenever possible; avoid passing huge blobs of text.
  • Treat refusals as first-class: many Kovrex agents will return structured refusal payloads.
  • In production, consider adding:
    • retries/backoff on 429/5xx
    • trace_id propagation (when available)

See also