> ## Documentation Index
> Fetch the complete documentation index at: https://docs.nebulaonchain.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# On-Chain Agent Identity and Reputation with Stellar8004

> Nebula registers your agent on Stellar8004, giving it a verifiable on-chain identity NFT and a reputation score other agents can trust.

When your agent makes payments, calls APIs, and interacts with other services on Stellar, it is just a public key — anonymous and without history. Stellar8004, built by Trion Labs, changes that: it mints an on-chain identity NFT for your agent's wallet address, creating a persistent, verifiable record of who your agent is and how it has behaved. Every payment and transaction that flows through your agent's wallet contributes to a reputation score that other agents and services can inspect before deciding whether to trust you.

## What Stellar8004 is

Stellar8004 is an adaptation of the ERC-8004 agent identity standard, implemented as a Soroban smart contract on Stellar. When your agent calls `register_identity`, a non-fungible identity token is minted and linked to your wallet's public key (`G...`). This NFT serves as your agent's on-chain passport — a stable identifier that persists across sessions, deployments, and upgrades.

The identity is **tied to your keypair**, not to the Nebula MCP server itself. If you migrate to a new deployment but keep the same `STELLAR_SECRET_KEY`, your agent retains its identity and reputation history.

## Why it matters

An anonymous wallet address tells a counterparty nothing about the agent behind it. An 8004 identity turns that address into a traceable track record:

* **Verifiable history**: every on-chain action your agent takes accumulates against its identity, creating an auditable log.
* **Reputation score**: clients and services that interact with your agent can leave feedback. Your agent's average score, feedback count, and number of unique clients are readable by anyone on-chain.
* **Inter-agent trust**: in a multi-agent economy, agents can query each other's reputation before entering into payment channels, MPP sessions, or data-sharing arrangements.
* **Discovery**: a named, described agent with a profile image is more discoverable than a raw public key.

## Identity tools

| Tool                | Parameters | What it does                                                                                                                        |
| ------------------- | ---------- | ----------------------------------------------------------------------------------------------------------------------------------- |
| `register_identity` | —          | Mints the ERC-8004 agent NFT for your wallet address. Safe to call multiple times — idempotent if your agent is already registered. |
| `get_my_reputation` | —          | Returns your agent's feedback count, average reputation score, and number of unique clients who have submitted feedback.            |

## Registering your agent

Registration is a single tool call:

```
Use register_identity from Nebula
```

Nebula submits a Soroban transaction that mints the identity NFT to your wallet address. The tool returns your agent ID and links to the explorer where the registration is visible on-chain. If your agent is already registered, calling `register_identity` again is safe — it returns the existing identity rather than creating a duplicate.

## Agent metadata

Enrich your agent's on-chain profile with optional environment variables. These fields are stored with the identity NFT and visible to anyone who looks up your agent on-chain:

| Variable                | Purpose                                   | Example                                         |
| ----------------------- | ----------------------------------------- | ----------------------------------------------- |
| `AGENT8004_NAME`        | Human-readable name for your agent        | `"Nebula Payment Agent"`                        |
| `AGENT8004_DESCRIPTION` | Short description of what your agent does | `"Automates API payments and yield on Stellar"` |
| `AGENT8004_IMAGE_URL`   | URL to an avatar or logo image            | `"https://example.com/agent-avatar.png"`        |

```json title="Identity metadata in mcp.json" theme={null}
{
  "mcpServers": {
    "nebula": {
      "command": "npx",
      "args": ["-y", "nebula-mcp"],
      "env": {
        "STELLAR_SECRET_KEY": "S...",
        "NETWORK": "testnet",
        "AGENT8004_NAME": "My Payment Agent",
        "AGENT8004_DESCRIPTION": "Pays for data APIs and earns yield on idle USDC",
        "AGENT8004_IMAGE_URL": "https://example.com/avatar.png"
      }
    }
  }
}
```

## Checking your reputation

```
Use get_my_reputation from Nebula
```

The output includes:

* **Feedback count**: total number of reviews submitted by clients
* **Average score**: your agent's mean reputation score across all feedback
* **Unique clients**: number of distinct counterparties who have submitted feedback

<Note>
  Reputation is built over time through real interactions. A freshly registered agent will have zero feedback — this is expected. As your agent makes payments and provides value to counterparties, feedback accumulates and the score becomes meaningful.
</Note>

## Testnet and mainnet contracts

By default, Nebula uses Stellar8004 **testnet contracts**. When you are ready to go to production, set `NETWORK=mainnet` in your MCP environment — Nebula will automatically use the mainnet Stellar8004 contracts for identity registration and reputation queries.

<Warning>
  Testnet and mainnet identities are separate. A testnet registration does not carry over to mainnet. Register your agent on mainnet before relying on its reputation in production interactions.
</Warning>

<CardGroup cols={2}>
  <Card title="Wallet" icon="wallet" href="/concepts/wallet">
    Set up your agent's Stellar wallet first
  </Card>

  <Card title="Payments" icon="bolt" href="/concepts/payments">
    Learn how x402 and MPP payments build your agent's track record
  </Card>
</CardGroup>