Overview
# Overview
Self Agent ID is an on-chain registry that binds an AI agent's key to a Self human proof. A human scans their passport once with the Self app, the agent gets a **soulbound ERC-721 NFT**, and the agent signs every request with its own key. Services check the signature and the on-chain proof, with no API key and no central server in the verification path.
The registry implements [ERC-8004](https://eips.ethereum.org/EIPS/eip-8004) with a [Proof-of-Human extension](/docs/agent-id/erc-8004/).
## Who this is for
| Audience | What you do | Start here |
| ---------------------------- | ---------------------------------------------------------- | ------------------------------------------------------------------- |
| **Agent builders** | Register an agent, sign outbound requests with `SelfAgent` | [Building an agent](/docs/agent-id/guides/agent-builder/) |
| **Service and API teams** | Verify inbound agent requests with `SelfAgentVerifier` | [Verifying agents](/docs/agent-id/guides/service-operator/) |
| **Protocol and infra teams** | Gate contracts and read the registry on-chain | [Gating smart contracts](/docs/agent-id/guides/contract-developer/) |
| **AI coding assistants** | Register, look up and verify agents through MCP | [Using the MCP server](/docs/agent-id/guides/mcp-user/) |
## How it works
1. **The human scans a QR code** with the Self app, which generates a ZK proof on the phone.
2. **Hub V2 verifies the proof** on-chain and calls the registry.
3. **The registry mints a soulbound NFT** that binds the agent key to the human's nullifier.
4. **The agent signs requests**, and services check the signature and the registry.
An agent is **verified** when `hasHumanProof && isProofFresh`. The SDK, the API and the contracts all apply this rule.
:::note
No personal data leaves the user's device. Only the proof result, a nullifier and any credentials the human chose to disclose are stored on-chain.
:::
## Key properties
- **Trustless**: verification reads the on-chain registry.
- **Private**: ZK proofs, and each credential is disclosed only if the human opts in.
- **Sybil-resistant**: one nullifier per human, and the registry caps agents per human (default 1).
- **Time-bounded**: proofs expire at `min(document expiry, registration + 365 days)` and can be refreshed in place.
- **Composable**: one registry call from any EVM contract, backend or agent framework.
## Networks
| Network | API name | Chain ID | Registry | Documents |
| ------------ | --------- | ---------- | -------------------------------------------- | ------------------------------------------------------------------------- |
| Celo Mainnet | `mainnet` | `42220` | `0xaC3DF9ABf80d0F5c020C06B04Cced27763355944` | Real passports and ID cards |
| Celo Sepolia | `testnet` | `11142220` | `0x043DaCac8b0771DD5b444bCC88f2f8BBDBEdd379` | [Mock passports](/docs/self-enterprise/guides/using-mock-passports/) only |
:::warning
Each network accepts only its own kind of document. A real passport fails on Celo Sepolia with `InvalidIdentityCommitmentRoot`, and a mock passport fails on Celo Mainnet. The SDK, A2A and MCP default to `mainnet`; the CLI defaults to `testnet`.
:::
## Ways to use it
| Interface | Use it for |
| ------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------- |
| TypeScript SDK [`@selfxyz/agent-sdk`](/docs/agent-id/sdk-integration/) | Registering, signing requests, verifying requests (the only official SDK) |
| [REST API](/docs/agent-id/rest-api/) at `https://agent-api.self.xyz` | Registration sessions and agent queries from any language, plus A2A and discovery |
| [MCP server](/docs/agent-id/guides/mcp-user/) at `https://agent-api.self.xyz/api/mcp` | AI coding assistants |
| [Local MCP server](/docs/agent-id/guides/mcp-user/#local-server) `@selfxyz/mcp-server` | AI coding assistants that sign as your own agent |
| [`self-agent` CLI](/docs/agent-id/cli/) | Registering from a terminal |
| [Smart contracts](/docs/agent-id/smart-contracts/) | On-chain gating and reads |
Other languages call the REST API and implement the [request-signing scheme](/docs/agent-id/sdk-integration/#signing-scheme) directly. Source: [github.com/selfxyz/self-agent-id](https://github.com/selfxyz/self-agent-id).
## Next steps
- [Register an agent with the SDK](/docs/agent-id/register-an-agent/): register, sign and verify in a few lines
- [Registration modes](/docs/agent-id/registration-modes/): pick the key type and ownership model
- [Verification patterns](/docs/agent-id/verification-patterns/): service, peer and on-chain checks
- [Smart contracts](/docs/agent-id/smart-contracts/): the registry, reputation, validation and visa contracts
- [REST API](/docs/agent-id/rest-api/): every endpoint, auth and rate limit
Read https://docs.self.xyz/docs/agent-id/overview.md so I can ask questions about this Self documentation page.
Self Agent ID is an on-chain registry that binds an AI agent’s key to a Self human proof. A human scans their passport once with the Self app, the agent gets a soulbound ERC-721 NFT, and the agent signs every request with its own key. Services check the signature and the on-chain proof, with no API key and no central server in the verification path.
The registry implements ERC-8004 with a Proof-of-Human extension.
Who this is for
| Audience | What you do | Start here |
|---|---|---|
| Agent builders | Register an agent, sign outbound requests with SelfAgent | Building an agent |
| Service and API teams | Verify inbound agent requests with SelfAgentVerifier | Verifying agents |
| Protocol and infra teams | Gate contracts and read the registry on-chain | Gating smart contracts |
| AI coding assistants | Register, look up and verify agents through MCP | Using the MCP server |
How it works
- The human scans a QR code with the Self app, which generates a ZK proof on the phone.
- Hub V2 verifies the proof on-chain and calls the registry.
- The registry mints a soulbound NFT that binds the agent key to the human’s nullifier.
- The agent signs requests, and services check the signature and the registry.
An agent is verified when hasHumanProof && isProofFresh. The SDK, the API and the contracts all apply this rule.
Key properties
- Trustless: verification reads the on-chain registry.
- Private: ZK proofs, and each credential is disclosed only if the human opts in.
- Sybil-resistant: one nullifier per human, and the registry caps agents per human (default 1).
- Time-bounded: proofs expire at
min(document expiry, registration + 365 days)and can be refreshed in place. - Composable: one registry call from any EVM contract, backend or agent framework.
Networks
| Network | API name | Chain ID | Registry | Documents |
|---|---|---|---|---|
| Celo Mainnet | mainnet | 42220 | 0xaC3DF9ABf80d0F5c020C06B04Cced27763355944 | Real passports and ID cards |
| Celo Sepolia | testnet | 11142220 | 0x043DaCac8b0771DD5b444bCC88f2f8BBDBEdd379 | Mock passports only |
Ways to use it
| Interface | Use it for |
|---|---|
TypeScript SDK @selfxyz/agent-sdk | Registering, signing requests, verifying requests (the only official SDK) |
REST API at https://agent-api.self.xyz | Registration sessions and agent queries from any language, plus A2A and discovery |
MCP server at https://agent-api.self.xyz/api/mcp | AI coding assistants |
Local MCP server @selfxyz/mcp-server | AI coding assistants that sign as your own agent |
self-agent CLI | Registering from a terminal |
| Smart contracts | On-chain gating and reads |
Other languages call the REST API and implement the request-signing scheme directly. Source: github.com/selfxyz/self-agent-id.
Next steps
- Register an agent with the SDK: register, sign and verify in a few lines
- Registration modes: pick the key type and ownership model
- Verification patterns: service, peer and on-chain checks
- Smart contracts: the registry, reputation, validation and visa contracts
- REST API: every endpoint, auth and rate limit
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