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

# AL0013 - Missing telemetry schema URL

> Setting the schema URL allows collectors and backends to understand which version of semantic conventions your telemetry uses

Source: [AL0013MissingSchemaUrlAnalyzer.cs](https://github.com/ANcpLua/ANcpLua.Analyzers/blob/main/src/ANcpLua.Analyzers/Analyzers/AL0013MissingSchemaUrlAnalyzer.cs)

## Description

Setting the schema URL allows collectors and backends to understand which version of semantic conventions your telemetry uses.

## Bad Code

```csharp theme={null}
using var activity = source.StartActivity("operation");
```

## Good Code

```csharp theme={null}
source.SetSchemaUrl("https://opentelemetry.io/schemas/1.21.0");
```

## Properties

* **Category**: OpenTelemetry
* **Severity**: Info
* **Enabled by default**: True
* **Code fix available**: False

## Configuration

```editorconfig theme={null}
dotnet_diagnostic.AL0013.severity = warning
```