langchain - 💡(How to fix) Fix Feature: Behavioral trust scoring layer for agent interactions [1 participants]

Submission checklist

• This is a feature request, not a bug report or usage question.
• I added a clear and descriptive title that summarizes the feature request.
• I used the GitHub search to find a similar feature request and didn't find it.
• I checked the LangChain documentation and API reference to see if this feature already exists.
• This is not related to the langchain-community package.

Package (Required)

• langchain
• langchain-openai
• langchain-anthropic
• langchain-classic
• langchain-core
• langchain-model-profiles
• langchain-tests
• langchain-text-splitters
• langchain-chroma
• langchain-deepseek
• langchain-exa
• langchain-fireworks
• langchain-groq
• langchain-huggingface
• langchain-mistralai
• langchain-nomic
• langchain-ollama
• langchain-openrouter
• langchain-perplexity
• langchain-qdrant
• langchain-xai
• Other / not sure / general

Feature Description

Add a behavioral trust scoring layer (beforeSettle hook) that evaluates agent/MCP server trustworthiness before executing paid actions or sensitive operations. This would use the x402 Trust-Provider Interface spec and the Dominion Observatory API (4,500+ monitored MCP servers).

Use Case

When building multi-agent systems, there's no standardized way to check whether an external agent or MCP server is trustworthy before executing a paid action. The agent economy is growing rapidly — LangChain agents call external MCP servers, paid APIs, and blockchain settlement. Without a trust layer, developers either skip trust checks entirely or build ad-hoc solutions.

The x402 HTTP 402 payment protocol is being adopted and needs a trust-provider interface to gate settlements. The Dominion Observatory already provides this data via a simple REST API:

curl https://dominion-observatory.sgdata.workers.dev/api/agent-query/{agent-id}

Returns: trust_score (0-100), behavioral metrics, attestation data.

Proposed Solution

A TrustGateCallback or middleware that runs before tool execution:

from langchain_core.callbacks import CallbackHandler

class TrustGateCallback(CallbackHandler):
    def on_tool_start(self, tool, input_str, **kwargs):
        score = observatory.query(tool.agent_id)
        if score.decision == 'FAIL':
            raise TrustGateError(f'Agent below trust threshold')

Reference implementation with working testnet demo: https://github.com/vdineshk/daee-engine/tree/main/testnet-demo Integration guide (5-line example): https://github.com/vdineshk/daee-engine/blob/main/docs/INTEGRATE.md x402 Trust-Provider Spec v0.1: https://github.com/vdineshk/daee-engine/blob/main/specs/x402-trust-provider-interface/v0.1/SPEC.md

Alternatives Considered

Currently there is no standardized trust evaluation for agent interactions. Developers either manually check APIs or trust everything by default. The x402 Trust-Provider Interface provides an open specification that any framework can adopt.

Additional Context

Observatory dashboard: https://dominion-observatory.sgdata.workers.dev Observatory API stats: https://dominion-observatory.sgdata.workers.dev/api/stats Spec: https://github.com/vdineshk/daee-engine/blob/main/specs/x402-trust-provider-interface/v0.1/SPEC.md