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

# Connectors

> Connector discovery — MCP servers and onchain tools.

Connectors are external integrations that extend what an agent can do. When an agent needs a capability it doesn't have built in — querying a database, reading an onchain oracle, calling an external API — it searches for a connector. The tool name for this is `connectors_find`.

## Two origins

Connectors come from two sources:

* **MCP servers** — Model Context Protocol servers that expose tools, resources, and prompts. These are standard integrations that any MCP-compatible client can use.
* **Onchain tools** — Smart-contract-based integrations onchain. Examples include Chainlink price feeds, onchain data oracles, and contract reads/writes. The agent treats these like any other connector but routes the call through the chain.

The agent does not distinguish between the two at the event level — both surface as `connectors_find` events. The `display` metadata on the raw event tells you which origin a given connector came from.

## Event shape

A parsed connector tool event has these fields:

| Field       | Type             | Meaning                                            |
| ----------- | ---------------- | -------------------------------------------------- |
| `start`     | `boolean`        | `true` when discovery begins, `false` when it ends |
| `connector` | `string`         | The connector identifier the agent selected        |
| `action`    | `string`         | What the agent asked the connector to do           |
| `result`    | `object \| null` | The connector output, available on `tool_end`      |
| `error`     | `string \| null` | Error message if the call failed                   |

## Stream example

```typescript theme={null}
for await (const event of stream) {
  if (event.type === "tool_start" && event.toolName === "connectors_find") {
    const tool = parseToolEvent(event);
    console.log(`Finding connector for: ${tool?.action}`);
  }
  if (event.type === "tool_end" && event.toolName === "connectors_find") {
    const tool = parseToolEvent(event);
    if (tool?.error) {
      console.error(`Connector call failed: ${tool.error}`);
    } else {
      console.log(`Connector resolved: ${tool?.connector}`);
    }
  }
}
```

## Display metadata

The `display` object includes a human-readable connector name and summary. Check `display.kind` to see the origin:

```typescript theme={null}
if (event.type === "tool_end" && event.toolName === "connectors_find") {
  const { name, summary, kind } = event.display ?? {};
  // name: "Chainlink Price Feed"
  // summary: "Fetch latest ETH/USD price"
  // kind: tells you the connector origin
  console.log(`${name}: ${summary}`);
}
```