# Trace Attributes

You can add/edit a custom trace attribute using the following APIs, passing a `string` key and a `string` value.

{% tabs fullWidth="true" %}
{% tab title="iOS - Swift" %}

```swift
let urlPattern = "*.example.com/*"
let urlPredicate = NSPredicate(format: "SELF LIKE[c] '\(urlPattern)'")
APM.addNetworkTraceAttributesForURL(matching: urlPredicate, owner: self) { trace in
    return [
        "trace": "example"
    ]
}
```

{% endtab %}

{% tab title="iOS - ObjC" %}

```objectivec
[LCQAPM addNetworkTraceAttributesForURLMatchingPredicate:[NSPredicate predicateWithFormat:@"SELF LIKE[c] '%@'", @"*.example.com/*"]
                                                   owner:self
                                            usingHandler:^NSDictionary<NSString *,NSString *> * _Nullable(LCQNetworkTrace * _Nonnull networkTrace) {
    return @{
        @"type": @"example"
    };
}];
```

{% endtab %}

{% tab title="And - Java" %}

```java
APM.addOnNetworkTraceListener(new OnNetworkTraceListener(
    new UrlPredicate() {
        @Override
        public boolean check(@NonNull String url) {
            // Add filter here the URL 
            // return boolean
        }
    }); 
    {
        @Override
        public Map<String, String> addAttributesOnFinish(NetworkTrace trace) {
            Map<String, String> map;
            map.put("Key", "Value");
            // Up to five attributes
            return map;
        }
    }
);
```

{% endtab %}

{% tab title="And - Kotlin" %}

```kotlin
APM.addOnNetworkTraceListener(
    object: OnNetworkTraceListener(
                UrlPredicate { url:String ->
                    // Add filter here the URL 
                    // return boolean
                }
    )
    {
        override fun addAttributesOnFinish(trace: NetworkTrace?): MutableMap<String, String?> {
            // Return map of Pairs (i.e. keys and values)
            return mutableMapOf(
                        // Up to five attributes
                    Pair("Key", "Value")
            )
        }
    }
)
```

{% endtab %}
{% endtabs %}


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.luciq.ai/references/application-performance-monitoring/network/trace-attributes.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.