> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.runtype.com/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.runtype.com/_mcp/server.

# Read a trace slice

GET https://api.runtype.com/v1/logs/trace/execution/{executionId}/slice

A bounded window of one trace: by span index range, span kind, tool name, or around the first failed span. Content stays previews-only unless includeContent is set, which loads it for the selected spans under a byte budget and lists every cut.

Reference: https://docs.runtype.com/api-reference/runtype-api/logs/read-a-trace-slice

## Authentication

- `Authorization` header (bearer token, required) — API key or Clerk session token

## Servers

- `https://api.runtype.com` (Production, default)
- `https://api.runtype-staging.com` (Staging)

## Request

### Path parameters

- `executionId` (string, required)

### Query parameters

- `start` (string, optional) — First span index (trace start order) to include.
- `end` (string, optional) — Span index to stop before.
- `kind` (enum, optional)
  - Allowed values: `model`, `tool`, `step`
- `toolName` (string, optional)
- `aroundFirstFailure` (string, optional) — Return the first failed span plus this many spans either side (0-50). Not combinable with start/end.
- `limit` (string, optional) — Spans to return, 1-100 (default 25).
- `includeContent` (enum, optional) — Load full content for the selected spans only, under maxContentBytes.
  - Allowed values: `true`, `false`
- `maxContentBytes` (string, optional) — Content byte budget, 1-262144 (default 65536).

## Response

### 200

Trace slice

- `data` (TraceSlice, required)
- `success` (boolean, required)

## Errors

### 400 Bad Request Error

Unreadable filter, window over the cap, or too many runs to probe; `code` says which

- `error` (string, required)
- `code` (string, optional) — Stable error code. `insufficient_scope` marks an API key that lacks a scope this request needs.
- `details` (list of ErrorDetailsItems, optional)
- `requiredScopes` (list of string, optional) — On `insufficient_scope`: every API key scope this request needs.

### 401 Unauthorized Error

Unauthorized

- `error` (string, required)
- `code` (string, optional) — Stable error code. `insufficient_scope` marks an API key that lacks a scope this request needs.
- `details` (list of ErrorDetailsItems, optional)
- `requiredScopes` (list of string, optional) — On `insufficient_scope`: every API key scope this request needs.

### 403 Forbidden Error

API key lacks a read scope (FLOWS:READ, AGENTS:READ or ANALYTICS:READ)

- `error` (string, required)
- `code` (string, optional) — Stable error code. `insufficient_scope` marks an API key that lacks a scope this request needs.
- `details` (list of ErrorDetailsItems, optional)
- `requiredScopes` (list of string, optional) — On `insufficient_scope`: every API key scope this request needs.

### 404 Not Found Error

No trace for this execution

- `error` (string, required)
- `code` (string, optional) — Stable error code. `insufficient_scope` marks an API key that lacks a scope this request needs.
- `details` (list of ErrorDetailsItems, optional)
- `requiredScopes` (list of string, optional) — On `insufficient_scope`: every API key scope this request needs.

### 500 Internal Server Error

Internal server error

- `error` (string, required)
- `code` (string, optional) — Stable error code. `insufficient_scope` marks an API key that lacks a scope this request needs.
- `details` (list of ErrorDetailsItems, optional)
- `requiredScopes` (list of string, optional) — On `insufficient_scope`: every API key scope this request needs.

### 503 Service Unavailable Error

Log store temporarily unavailable; no entries or counts could be read

- `error` (string, required)
- `code` (string, optional) — Stable error code. `insufficient_scope` marks an API key that lacks a scope this request needs.
- `details` (list of ErrorDetailsItems, optional)
- `requiredScopes` (list of string, optional) — On `insufficient_scope`: every API key scope this request needs.

## Types

### TraceSlice

- `content` (TraceSliceContent, required)
- `executionId` (string, required)
- `matchedSpans` (double, required)
- `selection` (TraceSliceSelection, required)
- `source` (string, required)
- `spans` (list of TraceSliceSpansItems, required)
- `totalSpans` (double, required)
- `traceId` (string, required)
- `traceTruncated` (boolean, required) — The trace exceeded the span read ceiling.
- `truncated` (boolean, required) — More spans matched than were returned.

### ErrorDetailsItems

- `message` (string, required)
- `code` (string, optional) — Stable Runtype validation code (e.g. MISSING_REQUIRED_FIELD, INVALID_ENUM).
- `path` (string, optional) — Dotted JSON path to the offending field.
- `suggestion` (string, optional) — Actionable hint (allowed values, accepted range, …).

### TraceSliceContent

- `cut` (list of TraceSliceContentCutItems, required)
- `limitBytes` (double, required)
- `loaded` (boolean, required)
- `unavailable` (list of string, required)
- `usedBytes` (double, required)

### TraceSliceSelection

- `firstFailedIndex` (double, required, nullable)
- `from` (double, required)
- `mode` (enum, required)
  - Allowed values: `range`, `around_first_failure`
- `to` (double, required)

### TraceSliceSpansItems

- `cost` (double, required, nullable)
- `durationMs` (double, required, nullable)
- `error` (string, required, nullable)
- `index` (double, required)
- `inputPreview` (string, required, nullable)
- `inputTokens` (double, required, nullable)
- `kind` (string, required, nullable)
- `model` (string, required, nullable)
- `name` (string, required)
- `outputPreview` (string, required, nullable)
- `outputTokens` (double, required, nullable)
- `parentSpanId` (string, required, nullable)
- `spanId` (string, required, nullable)
- `startedAt` (string, required)
- `status` (string, required)
- `stopReason` (string, required, nullable)
- `toolName` (string, required, nullable)
- `content` (map from string to any, optional)

### TraceSliceContentCutItems

- `bytes` (double, required)
- `field` (string, required)
- `returnedBytes` (double, required)
- `spanId` (string, required)

## Examples

**Response**

```json
{
  "data": {
    "content": {
      "cut": [
        {
          "bytes": 1.1,
          "field": "string",
          "returnedBytes": 1.1,
          "spanId": "string"
        }
      ],
      "limitBytes": 1.1,
      "loaded": true,
      "unavailable": [
        "string"
      ],
      "usedBytes": 1.1
    },
    "executionId": "string",
    "matchedSpans": 1.1,
    "selection": {
      "firstFailedIndex": 1.1,
      "from": 1.1,
      "mode": "range",
      "to": 1.1
    },
    "source": "string",
    "spans": [
      {
        "cost": 1.1,
        "durationMs": 1.1,
        "error": "string",
        "index": 1.1,
        "inputPreview": "string",
        "inputTokens": 1.1,
        "kind": "string",
        "model": "string",
        "name": "string",
        "outputPreview": "string",
        "outputTokens": 1.1,
        "parentSpanId": "string",
        "spanId": "string",
        "startedAt": "string",
        "status": "string",
        "stopReason": "string",
        "toolName": "string",
        "content": {}
      }
    ],
    "totalSpans": 1.1,
    "traceId": "string",
    "traceTruncated": true,
    "truncated": true
  },
  "success": true
}
```

**SDK Code**

```python
import requests

url = "https://api.runtype.com/v1/logs/trace/execution/executionId/slice"

headers = {"Authorization": "Bearer <token>"}

response = requests.get(url, headers=headers)

print(response.json())
```

```javascript
const url = 'https://api.runtype.com/v1/logs/trace/execution/executionId/slice';
const options = {method: 'GET', headers: {Authorization: 'Bearer <token>'}};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go
package main

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

func main() {

	url := "https://api.runtype.com/v1/logs/trace/execution/executionId/slice"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("Authorization", "Bearer <token>")

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

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

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

}
```

```ruby
require 'uri'
require 'net/http'

url = URI("https://api.runtype.com/v1/logs/trace/execution/executionId/slice")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Get.new(url)
request["Authorization"] = 'Bearer <token>'

response = http.request(request)
puts response.read_body
```

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

HttpResponse<String> response = Unirest.get("https://api.runtype.com/v1/logs/trace/execution/executionId/slice")
  .header("Authorization", "Bearer <token>")
  .asString();
```

```php
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('GET', 'https://api.runtype.com/v1/logs/trace/execution/executionId/slice', [
  'headers' => [
    'Authorization' => 'Bearer <token>',
  ],
]);

echo $response->getBody();
```

```csharp
using RestSharp;

var client = new RestClient("https://api.runtype.com/v1/logs/trace/execution/executionId/slice");
var request = new RestRequest(Method.GET);
request.AddHeader("Authorization", "Bearer <token>");
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = ["Authorization": "Bearer <token>"]

let request = NSMutableURLRequest(url: NSURL(string: "https://api.runtype.com/v1/logs/trace/execution/executionId/slice")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "GET"
request.allHTTPHeaderFields = headers

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()
```