# RunLabels
> Tracon documentation. Tracon is a .NET package family that adds a control
> plane on Microsoft Agent Framework, published as NuGet packages that run
> inside your own ASP.NET Core application.
>
> Page: https://tracon.dev/api/tracon.runlabels/
> Summary: RunLabels: The limits a run's attribution must obey, and the single place they are enforced.
Namespace Tracon · Assembly Tracon.Abstractions.dll
The limits a run's attribution must obey, and the single place they are enforced.
```csharp
public static class RunLabels
```
- Inheritance
- object ← RunLabels
- Inherited Members
- object.GetType(), object.MemberwiseClone(), object.ToString(), object.Equals(object?), object.Equals(object?, object?), object.ReferenceEquals(object?, object?), object.GetHashCode()
## Remarks
Labels answer "which job was this run made for". They are a small
`string`-to-`string` map, kept deliberately small: a run label is
a query dimension, and an unbounded set of them turns every breakdown query
into a scan over an unbounded key space.
Breaking a limit REJECTS the value; it is never trimmed. A trimmed label
set still looks like a complete measurement to whoever reads the report
later, and that is worse than an error at the boundary.
## Fields
### MaxCount
The largest number of labels one run may carry.
```csharp
public const int MaxCount = 8
```
#### Field Value
[int](https://learn.microsoft.com/dotnet/api/system.int32)
### MaxKeyLength
The largest length of a label key.
```csharp
public const int MaxKeyLength = 64
```
#### Field Value
[int](https://learn.microsoft.com/dotnet/api/system.int32)
#### Remarks
A key is usable as a breakdown dimension, so it stays short enough to group by.
### MaxUserIdLength
The largest length of a user identity.
```csharp
public const int MaxUserIdLength = 200
```
#### Field Value
[int](https://learn.microsoft.com/dotnet/api/system.int32)
#### Remarks
The value is stored in an INDEXED column. SQL Server cannot index
`nvarchar(max)`, so every indexed key column in this schema is
bounded at 200 characters; the limit here matches that column.
### MaxValueLength
The largest length of a label value.
```csharp
public const int MaxValueLength = 256
```
#### Field Value
[int](https://learn.microsoft.com/dotnet/api/system.int32)
#### Remarks
This is not a free-text store; longer content belongs in the run's own event stream.
## Methods
### Freeze\(IReadOnlyDictionary\)
Copies a label set into an immutable, ordinally compared dictionary.
```csharp
public static IReadOnlyDictionary Freeze(IReadOnlyDictionary labels)
```
#### Parameters
`labels` [IReadOnlyDictionary](https://learn.microsoft.com/dotnet/api/system.collections.generic.ireadonlydictionary\-2)<[string](https://learn.microsoft.com/dotnet/api/system.string), [string](https://learn.microsoft.com/dotnet/api/system.string)\>
The labels to copy.
#### Returns
[IReadOnlyDictionary](https://learn.microsoft.com/dotnet/api/system.collections.generic.ireadonlydictionary\-2)<[string](https://learn.microsoft.com/dotnet/api/system.string), [string](https://learn.microsoft.com/dotnet/api/system.string)\>
A snapshot that later writes to the source cannot change.
#### Remarks
The caller's dictionary may be mutable and may even be a live request
object; a run record must not change under the reader after the run ends.
#### Exceptions
[ArgumentNullException](https://learn.microsoft.com/dotnet/api/system.argumentnullexception)
`labels` is [null](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null).
### Validate\(string?, IReadOnlyDictionary?\)
Checks a complete attribution.
```csharp
public static string? Validate(string? userId, IReadOnlyDictionary? labels)
```
#### Parameters
`userId` [string](https://learn.microsoft.com/dotnet/api/system.string)?
The user identity, or [null](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null).
`labels` [IReadOnlyDictionary](https://learn.microsoft.com/dotnet/api/system.collections.generic.ireadonlydictionary\-2)<[string](https://learn.microsoft.com/dotnet/api/system.string), [string](https://learn.microsoft.com/dotnet/api/system.string)\>?
The labels, or [null](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null).
#### Returns
[string](https://learn.microsoft.com/dotnet/api/system.string)?
[null](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null) when the value is acceptable, otherwise a message
naming the limit that was broken.
### ValidateLabels\(IReadOnlyDictionary?\)
Checks a label set on its own.
```csharp
public static string? ValidateLabels(IReadOnlyDictionary? labels)
```
#### Parameters
`labels` [IReadOnlyDictionary](https://learn.microsoft.com/dotnet/api/system.collections.generic.ireadonlydictionary\-2)<[string](https://learn.microsoft.com/dotnet/api/system.string), [string](https://learn.microsoft.com/dotnet/api/system.string)\>?
The labels, or [null](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null).
#### Returns
[string](https://learn.microsoft.com/dotnet/api/system.string)?
[null](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null) when the value is acceptable, otherwise a message.
### ValidateUserId\(string?\)
Checks a user identity on its own.
```csharp
public static string? ValidateUserId(string? userId)
```
#### Parameters
`userId` [string](https://learn.microsoft.com/dotnet/api/system.string)?
The user identity, or [null](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null).
#### Returns
[string](https://learn.microsoft.com/dotnet/api/system.string)?
[null](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null) when the value is acceptable, otherwise a message.