For clean Markdown of any page, append .md to the page URL. For a complete documentation index, see https://you.com/docs/custom-solutions/agents/express-agent/llms.txt. For full documentation content, see https://you.com/docs/custom-solutions/agents/express-agent/llms-full.txt.

# Express Agent

POST https://api.you.com/v1/agents/runs
Content-Type: application/json

This endpoint answers the user’s query with an LLM. Optionally, you can ground the answer using web results (max 1 web search).

Use it for answering simple questions that require a low latency response.

The data returns as SSE (Server-Side Events) with the `text/event-stream` content type in the response header.

<Info> This call streams data as the agent responds.</Info>

Reference: https://you.com/docs/custom-solutions/agents/express-agent/express-agent-runs

## OpenAPI Specification

```yaml
openapi: 3.1.0
info:
  title: express
  version: 1.0.0
paths:
  /v1/agents/runs:
    post:
      operationId: express-agent-runs-stream
      summary: Express Agent
      description: >-
        This endpoint answers the user’s query with an LLM. Optionally, you can
        ground the answer using web results (max 1 web search).


        Use it for answering simple questions that require a low latency
        response.


        The data returns as SSE (Server-Side Events) with the
        `text/event-stream` content type in the response header.


        <Info> This call streams data as the agent responds.</Info>
      tags:
        - ''
      parameters:
        - name: Authorization
          in: header
          description: Bearer authentication
          required: true
          schema:
            type: string
      responses:
        '200':
          description: ''
          content:
            text/event-stream:
              schema:
                $ref: '#/components/schemas/type_:ExpressAgentRunsStreamingResponse'
        '400':
          description: The Authorization Bearer token was missing or invalid
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/type_:AgentRuns400Response'
        '422':
          description: When the request data coming in is invalid
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/type_:AgentRuns422Response'
      requestBody:
        content:
          application/json:
            schema:
              type: object
              properties:
                agent:
                  $ref: >-
                    #/components/schemas/type_:ExpressAgentRunsStreamRequestAgent
                  description: >-
                    Setting this value to "express" is mandatory to use the
                    express agent.
                input:
                  type: string
                  description: The question you'd like to ask the agent
                stream:
                  type: boolean
                  enum:
                    - true
                  description: >-
                    Must be set to `true` when you want to stream the express
                    agent response as its being generated, and `false` when you
                    want the response to return after the agent has finished.
                tools:
                  type: array
                  items:
                    $ref: >-
                      #/components/schemas/type_:ExpressAgentRunsStreamRequestToolsItem
                  description: >-
                    You can optionally ground the express agent response using
                    results fetched from the web (max 1 web search)
              required:
                - agent
                - input
                - stream
servers:
  - url: https://api.you.com
components:
  schemas:
    type_:ExpressAgentRunsStreamRequestAgent:
      type: string
      enum:
        - express
      description: Setting this value to "express" is mandatory to use the express agent.
      title: ExpressAgentRunsStreamRequestAgent
    type_:ExpressAgentRunsStreamRequestToolsItemType:
      type: string
      enum:
        - web_search
      description: >-
        Setting this value to "web_search" is mandatory to use the web_search
        tool.
      title: ExpressAgentRunsStreamRequestToolsItemType
    type_:ExpressAgentRunsStreamRequestToolsItem:
      type: object
      properties:
        type:
          $ref: >-
            #/components/schemas/type_:ExpressAgentRunsStreamRequestToolsItemType
          description: >-
            Setting this value to "web_search" is mandatory to use the
            web_search tool.
      required:
        - type
      title: ExpressAgentRunsStreamRequestToolsItem
    type_:ResponseCreatedType:
      type: string
      enum:
        - response.created
      title: ResponseCreatedType
    type_:ResponseStartingType:
      type: string
      enum:
        - response.starting
      title: ResponseStartingType
    type_:ResponseOutputItemAddedType:
      type: string
      enum:
        - response.output_item.added
      title: ResponseOutputItemAddedType
    type_:ResponseOutputItemAddedResponse:
      type: object
      properties:
        output_index:
          type: integer
          description: The index of the output item in the response
      required:
        - output_index
      title: ResponseOutputItemAddedResponse
    type_:ResponseOutputContentFullType:
      type: string
      enum:
        - response.output_content.full
      title: ResponseOutputContentFullType
    type_:ResponseOutputContentFullResponseType:
      type: string
      enum:
        - web_search.results
      title: ResponseOutputContentFullResponseType
    type_:AgentRunsResponseWebSearchResultSourceType:
      type: string
      enum:
        - web_search
      description: The type of content the agent can return outside a text response
      title: AgentRunsResponseWebSearchResultSourceType
    type_:AgentRunsResponseWebSearchResult:
      type: object
      properties:
        source_type:
          $ref: >-
            #/components/schemas/type_:AgentRunsResponseWebSearchResultSourceType
          description: The type of content the agent can return outside a text response
        citation_uri:
          type: string
          description: The web search result the agent returned along in its response
        provider:
          type: string
          description: This is currently unused
        title:
          type: string
          description: The title of the web site returned under url
        snippet:
          type: string
          description: A textual portion of the web site returned under url
        thumbnail_url:
          type: string
          description: The thumbnail image of the url
        url:
          type: string
          description: The web search result the agent returned along in its response
      required:
        - source_type
        - citation_uri
        - title
        - snippet
        - url
      description: >-
        The text response of the agent. This field only returns when the type is
        `web_search.results`
      title: AgentRunsResponseWebSearchResult
    type_:ResponseOutputContentFullResponse:
      type: object
      properties:
        output_index:
          type: integer
        type:
          $ref: '#/components/schemas/type_:ResponseOutputContentFullResponseType'
        full:
          type: array
          items:
            $ref: '#/components/schemas/type_:AgentRunsResponseWebSearchResult'
          description: Complete web search results
      required:
        - output_index
        - type
        - full
      title: ResponseOutputContentFullResponse
    type_:ResponseOutputItemDoneType:
      type: string
      enum:
        - response.output_item.done
      title: ResponseOutputItemDoneType
    type_:ResponseOutputItemDoneResponse:
      type: object
      properties:
        output_index:
          type: integer
      required:
        - output_index
      title: ResponseOutputItemDoneResponse
    type_:ResponseOutputTextDeltaType:
      type: string
      enum:
        - response.output_text.delta
      title: ResponseOutputTextDeltaType
    type_:ResponseOutputTextDeltaResponseType:
      type: string
      enum:
        - message.answer
      title: ResponseOutputTextDeltaResponseType
    type_:ResponseOutputTextDeltaResponse:
      type: object
      properties:
        output_index:
          type: integer
        type:
          $ref: '#/components/schemas/type_:ResponseOutputTextDeltaResponseType'
        delta:
          type: string
          description: Incremental text content
      required:
        - output_index
        - type
        - delta
      title: ResponseOutputTextDeltaResponse
    type_:ResponseDoneType:
      type: string
      enum:
        - response.done
      title: ResponseDoneType
    type_:ResponseDoneResponse:
      type: object
      properties:
        run_time_ms:
          type: string
          description: Total runtime in milliseconds
        finished:
          type: boolean
          description: Whether the response is complete
      required:
        - run_time_ms
        - finished
      title: ResponseDoneResponse
    type_:ExpressAgentRunsStreamingResponse:
      oneOf:
        - type: object
          properties:
            type:
              $ref: '#/components/schemas/type_:ResponseCreatedType'
            seq_id:
              type: integer
          required:
            - type
            - seq_id
        - type: object
          properties:
            type:
              $ref: '#/components/schemas/type_:ResponseStartingType'
            seq_id:
              type: integer
          required:
            - type
            - seq_id
        - type: object
          properties:
            type:
              $ref: '#/components/schemas/type_:ResponseOutputItemAddedType'
            seq_id:
              type: integer
            response:
              $ref: '#/components/schemas/type_:ResponseOutputItemAddedResponse'
          required:
            - type
            - seq_id
            - response
        - type: object
          properties:
            type:
              $ref: '#/components/schemas/type_:ResponseOutputContentFullType'
            seq_id:
              type: integer
            response:
              $ref: '#/components/schemas/type_:ResponseOutputContentFullResponse'
          required:
            - type
            - seq_id
            - response
        - type: object
          properties:
            type:
              $ref: '#/components/schemas/type_:ResponseOutputItemDoneType'
            seq_id:
              type: integer
            response:
              $ref: '#/components/schemas/type_:ResponseOutputItemDoneResponse'
          required:
            - type
            - seq_id
            - response
        - type: object
          properties:
            type:
              $ref: '#/components/schemas/type_:ResponseOutputTextDeltaType'
            seq_id:
              type: integer
            response:
              $ref: '#/components/schemas/type_:ResponseOutputTextDeltaResponse'
          required:
            - type
            - seq_id
            - response
        - type: object
          properties:
            type:
              $ref: '#/components/schemas/type_:ResponseDoneType'
            seq_id:
              type: integer
            response:
              $ref: '#/components/schemas/type_:ResponseDoneResponse'
          required:
            - type
            - seq_id
            - response
      discriminator:
        propertyName: type
      description: Server-Sent Event (SSE) format for streaming agent responses
      title: ExpressAgentRunsStreamingResponse
    type_:AgentRuns400Response:
      type: object
      properties:
        detail:
          type: string
      description: The message returned by the error
      title: AgentRuns400Response
    type_:AgentRuns422ResponseDetailItemLocItem:
      oneOf:
        - type: string
        - type: integer
      title: AgentRuns422ResponseDetailItemLocItem
    type_:AgentRuns422ResponseDetailItem:
      type: object
      properties:
        type:
          type: string
        loc:
          type: array
          items:
            $ref: '#/components/schemas/type_:AgentRuns422ResponseDetailItemLocItem'
        msg:
          type: string
        input:
          type: string
      required:
        - type
        - loc
        - msg
        - input
      title: AgentRuns422ResponseDetailItem
    type_:AgentRuns422Response:
      type: object
      properties:
        detail:
          type: array
          items:
            $ref: '#/components/schemas/type_:AgentRuns422ResponseDetailItem'
      title: AgentRuns422Response
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer

```

## SDK Code Examples

```python
# Use our official Python SDK to stream the agent response
from youdotcom import You
from youdotcom.models import (
    ExpressAgentRunsRequest,
    ResponseOutputTextDelta,
    ResponseDone,
)

with You("api_key") as you:
  response = you.agents.runs.create(
    request=ExpressAgentRunsRequest(
      input="What are some great recipes I can make in under half an hour",
      stream=True
    )
  )

  with response as stream:
      for chunk in stream:
          event = chunk.data
          if isinstance(event, ResponseOutputTextDelta):
              print(event.response.delta, end="", flush=True)
          elif isinstance(event, ResponseDone):
              print(f"\nDone in {event.response.run_time_ms}ms")

```

```typescript
// Use our official TypeScript SDK to stream the agent response
import { You } from "@youdotcom-oss/sdk";
import type { ExpressAgentRunsRequest, AgentRunsStreamingResponse } from "@youdotcom-oss/sdk/models";
import type { EventStream } from "@youdotcom-oss/sdk/lib/event-streams.js";

const you = new You({ apiKeyAuth: "api_key" });

const request: ExpressAgentRunsRequest = {
  agent: "express",
  stream: true,
  input: "What are some great recipes I can make in under half an hour",
  tools: [{ type: "web_search" }]
};

const result = await you.agentsRuns(request) as EventStream<AgentRunsStreamingResponse>;

for await (const chunk of result) {
  if (chunk.data.type === "response.output_text.delta") {
    process.stdout.write(chunk.data.response.delta);
  }
}

```

```javascript
// Use our official JavaScript SDK to stream the agent response
import { You } from "@youdotcom-oss/sdk";

const you = new You({ apiKeyAuth: "api_key" });

const request = {
  agent: "express",
  stream: true,
  input: "What are some great recipes I can make in under half an hour",
  tools: [{ type: "web_search" }]
};

const result = await you.agentsRuns(request);

for await (const chunk of result) {
  if (chunk.data.type === "response.output_text.delta") {
    process.stdout.write(chunk.data.response.delta);
  }
}

```

```go
package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.you.com/v1/agents/runs"

	payload := strings.NewReader("{\n  \"agent\": \"express\",\n  \"input\": \"What are some great recipes I can make in under half an hour\",\n  \"stream\": true\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```java
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://api.you.com/v1/agents/runs")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"agent\": \"express\",\n  \"input\": \"What are some great recipes I can make in under half an hour\",\n  \"stream\": true\n}")
  .asString();
```

```csharp
using RestSharp;

var client = new RestClient("https://api.you.com/v1/agents/runs");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "Bearer <token>");
request.AddHeader("Content-Type", "application/json");
request.AddParameter("application/json", "{\n  \"agent\": \"express\",\n  \"input\": \"What are some great recipes I can make in under half an hour\",\n  \"stream\": true\n}", ParameterType.RequestBody);
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = [
  "Authorization": "Bearer <token>",
  "Content-Type": "application/json"
]
let parameters = [
  "agent": "express",
  "input": "What are some great recipes I can make in under half an hour",
  "stream": true
] as [String : Any]

let postData = JSONSerialization.data(withJSONObject: parameters, options: [])

let request = NSMutableURLRequest(url: NSURL(string: "https://api.you.com/v1/agents/runs")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers
request.httpBody = postData as Data

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```