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SperaxOS ERC-8004 Agent Metadata Setter
x402
SperaxOS ERC-8004 Agent Metadata Setter is a paid API for AI agents from chat.sperax.io, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-20).
Sets a metadata key-value pair on an ERC-8004 registered on-chain agent NFT across supported blockchains
Price / call$0.001
Success—
StatusUnknown
How this service works
AI-powered DeFi intelligence APIs payable via the x402 HTTP payment protocol. No API key required — pay per request with USDC on Base. Identity-only (SIWX) endpoints are free for wallets with an agentcash identity.
Output
A confirmation of the on-chain metadata update transaction, indicating that the specified key-value pair has been written to the ERC-8004 agent NFT record on the chosen blockchain.
Example use cases
Register A2A endpoint for on-chain agent
“Update my on-chain agent with token ID 7 on BSC mainnet to set its 'a2a.endpoint' metadata to 'https://agents.myproject.io/agent7/a2a' so other agents can discover and communicate with it.”
Link DID identity to agent NFT
“Set the 'did' metadata key to 'did:ethr:0xabc123...' for my ERC-8004 agent token ID 15 deployed on Ethereum mainnet so it has a verifiable decentralized identity.”
Enable x402 payments on registered agent
“For my agent with token ID 99 on BSC testnet, set the metadata key 'x402.enabled' to 'true' so it can accept per-request USDC micropayments via the x402 protocol.”
Technical details
Endpoint
POSThttps://chat.sperax.io/api/x402/tools/erc8004/setMetadata?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to write or update structured metadata fields on an ERC-8004 compliant agent NFT on a supported EVM chain. It is the right choice when configuring agent discovery properties (a2a.endpoint, mcp.endpoint, x402.enabled), linking identity documents (DID, ENS), or setting versioning metadata — especially within the SperaxOS / agentcash ecosystem where no traditional API key is required and payment is handled via x402 micropayments.
Side effects
- Invalid or non-existent agent token ID returns an error indicating the agent cannot be found
- Unsupported chain value causes a validation error listing accepted options
- Empty or missing key/value fields result in a schema validation error
- Caller wallet does not own or have permission to update the specified agent NFT
- Blockchain network congestion or RPC failure causes a transaction timeout
- Malformed metadata value (e.g. non-UTF-8 string) may be rejected
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| key | string | Metadata key (e.g., "version", "a2a.endpoint", "mcp.endpoint", "did", "ens", "x402.enabled") |
| chain | string | Blockchain where the agent is registered. Options: bsc-testnet, bsc-mainnet, ethereum, sepolia |
| value | string | Metadata value as a UTF-8 string |
| agentId | number | The token ID of the agent to update |
Tags
x402
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