AL0065 - Use gen_ai.client.token.usage histogram

Token metrics should use the standard histogram

Source: Al0065UseTokenUsageHistogramAnalyzer.cs

Description

Token usage metrics should use the gen_ai.client.token.usage histogram name defined in OpenTelemetry GenAI semantic conventions.

Bad Code

var counter = meter.CreateCounter<long>("token_count");
counter.Add(response.Usage.TotalTokens);

Good Code

var histogram = meter.CreateHistogram<long>("gen_ai.client.token.usage");
histogram.Record(response.Usage.TotalTokens,
    new("gen_ai.token.type", "total"));

Properties

• Category: GenAI
• Severity: Warning
• Enabled by default: True
• Code fix available: False

Configuration

dotnet_diagnostic.AL0065.severity = warning