feat: add agent identity verification tool (ERC-8004)

[up2itnow0822]

Summary

Adds an agent identity and reputation verification tool using ERC-8004 on-chain identity registries.

As agents interact with other agents (delegating tasks, purchasing services, sharing data), they need a way to verify who they're dealing with before transacting. This tool provides that trust layer.

Tools

verify_agent_identity — Full identity verification pipeline:

1. Queries the ERC-8004 registry for on-chain identity (ERC-721 token)
2. Checks reputation score against a configurable threshold
3. Verifies advertised capabilities match requirements
4. Detects revoked or expired identities
5. Returns a TRUST / REJECT / ERROR decision

lookup_agent_reputation — Detailed reputation lookup:

• Overall score and review counts
• Category-level scores (accuracy, reliability, speed, cost)
• Recent feedback entries with comments

Pattern

Same structure as x402_payment_tool:

• @register_function with FunctionBaseConfig subclass
• nat.components entry point registration
• react_agent workflow config with NIM LLM
• Mock server for e2e testing without blockchain access

Testing

Mock registry server includes 4 test agents:

Agent	Status	Reputation
0x1234...5678	Registered	87.5/100
0xdead...beef	Revoked	12.0/100
0xaaaa...aaaa	Expired	N/A
0x0000...0000	Not registered	N/A

Files

agent_identity_tool/
├── README.md
├── pyproject.toml
├── .gitignore
├── scripts/
│   └── mock_registry_server.py
└── src/nat_agent_identity/
    ├── __init__.py
    ├── register.py
    └── configs/
        └── identity-agent.example.yml

CI

Pre-commit (yapf, ruff, uv-lock, markdown-link-check), Vale, and copyright checks all passing locally.

Relationship to x402_payment_tool

Pairs with the x402 payment tool for trust-then-transact workflows: verify an agent's identity and reputation first, then pay for their service.

[copy-pr-bot]

This pull request requires additional validation before any workflows can run on NVIDIA's runners.

Pull request vetters can view their responsibilities here.

Contributors can view more details about this message here.

[up2itnow0822]

Quick update: PR #17 (agent-wallet-sdk payment tools) has been merged and is working well in production. This PR (#19) extends that foundation with MCP-native payment capabilities. Happy to address any feedback from maintainers — let me know if there's anything needed to move this forward.

[willkill07]

Please include exact input and expected output running NeMo Agent Toolkit. This also helps show that you have validated that the agent runs e2e.

[up2itnow0822]

Thanks, Will. Good call. I'll update the README to include the exact NeMo Agent Toolkit input, expected output, and the command flow used to validate the example end to end against the mock registry. That will make it clear the example was run and verified. Let me know if you need anything else.