Program ID: Bebty49EPhFoANKDw7TqLQ2bX61ackNav5iNkj36eVJo
x0-registry is the protocol’s agent discovery layer. Agents register with an endpoint URL and a set of capabilities, making themselves discoverable to other agents and services.
Instructions
register_agent
Registers a new agent in the discovery registry. Requires a listing fee of REGISTRY_LISTING_FEE_LAMPORTS = 100,000,000 (0.1 SOL).
register_agent(endpoint: String, capabilities: Vec<Capability>)
| Parameter | Type | Constraints |
|---|
endpoint | String | Max 256 bytes, must be a valid URL |
capabilities | Vec<Capability> | Max 10 capabilities per agent |
update_registry
Updates the agent’s endpoint and/or capabilities.
update_registry(
new_endpoint: Option<String>,
new_capabilities: Option<Vec<Capability>>
)
deactivate_entry
Marks the agent as inactive. The registry entry remains on-chain but is excluded from discovery queries.
reactivate_entry
Reactivates a previously deactivated entry.
deregister_agent
Permanently removes the agent from the registry and closes the account, reclaiming rent.
State Account
AgentRegistry
pub struct AgentRegistry {
pub version: u8,
pub agent_id: Pubkey,
pub endpoint: String, // Service URL (max 256 bytes)
pub capabilities: Vec<Capability>, // Up to 10 capabilities
pub price_oracle: Option<Pubkey>, // Optional price feed
pub reputation_pda: Pubkey, // Link to reputation account
pub last_updated: i64,
pub is_active: bool,
pub owner: Pubkey,
pub bump: u8,
}
["registry", agent_id]
Capability
Each capability describes a service the agent offers:
pub struct Capability {
pub capability_type: String, // e.g., "text-generation", "image-analysis"
pub metadata: String, // JSON metadata (max 256 bytes)
}
metadata field is a JSON string stored on-chain. It typically contains:
{
"model": "gpt-4",
"price_per_request": 1000000,
"max_tokens": 4096,
"supported_formats": ["text", "json"]
}
Discovery
Agents can be discovered by:
- Iterating registry PDAs — Use
getProgramAccounts with filters on capability_type
- SDK helper —
X0Client.findAgents(capabilityType) fetches and filters matching agents
- Reputation check — Each registry entry links to a reputation PDA for trust scoring
Registry Constants
| Constant | Value | Purpose |
|---|
REGISTRY_LISTING_FEE_LAMPORTS | 100,000,000 (0.1 SOL) | Anti-spam listing fee |
MAX_ENDPOINT_LENGTH | 256 bytes | Maximum URL length |
MAX_CAPABILITIES_PER_AGENT | 10 | Max capabilities per registration |
MAX_CAPABILITY_TYPE_LENGTH | 64 bytes | Max capability type string |
MAX_CAPABILITY_METADATA_LENGTH | 256 bytes | Max metadata JSON per capability |
REGISTRY_TTL_SECONDS | 300 (5 min) | Client-side cache TTL |
Events Emitted
| Event | When |
|---|
AgentRegistered | New agent registered |
RegistryUpdated | Endpoint or capabilities changed |
AgentDeregistered | Agent removed from registry |
Last modified on February 8, 2026
