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.

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