Document global attributes (#15279)

Author: cleptric

develop-docs/sdk/telemetry/scopes.mdx

@@ -52,6 +52,57 @@ Data from all three scope types MUST be merged in a specific order before being
 
 ![Scope Inheritance](scope-inheritance.png)
 
+## Scope Methods
+
+### Setting Attributes
+
+Users MUST be able to attach attributes to any scope using a dedicated method (e.g., `scope.setAttributes()` or `scope.setAttribute()`). These attributes follow the structure defined in the [Span Protocol](/sdk/telemetry/spans/span-protocol/#attribute-object-properties).
+
+Attributes are key-value pairs where each value is an object containing:
+
+- `type`: The data type (`"string"`, `"integer"`, `"double"`, `"boolean"`, `"string[]"`, `"integer[]"` and `"double[]"`)
+- `value`: The actual attribute value, which MUST match the specified type
+- `unit` (optional): The unit of measurement (e.g., `"ms"`, `"s"`, `"bytes"`, `"count"`, `"percent"`)
+
+#### Example Usage
+
+```javascript
+Sentry.getGlobalScope().setAttributes({
+  "app.feature_flag.enabled": true,
+  "app.session_duration": {
+    type: "integer",
+    value: 3600,
+    unit: "s"
+  }
+});
+```
+
+```python
+sentry_sdk.get_global_scope().set_attributes({
+    "app.feature_flag.enabled": True,
+    "app.session_duration": {
+        "type": "integer",
+        "value": 3600,
+        "unit": "s"
+    }
+})
+```
+
+#### Method Signature
+
+The method SHOULD accept a dictionary/map/object where:
+- Keys are attribute names (strings)
+- Values are attribute objects with `type`, `value`, and optionally `unit` properties
+
+#### Behavior
+
+- Attributes set on the global scope MUST be applied to all logs
+- Attributes set on the isolation scope MUST be applied to all logs in that execution context
+- Attributes set on the current scope MUST be applied only to the current log
+- When the same attribute key exists in multiple scopes, the more specific scope's value takes precedence (current > isolation > global)
+
+See [Span Protocol - Common Attribute Keys](/sdk/telemetry/spans/span-protocol/#common-attribute-keys) for a list of standard attributes and [Sentry Conventions](https://github.com/getsentry/sentry-conventions/) for the complete attribute registry.
+
 ## Related Documents
 
 This document provides a concise summary of the [Hub & Scope Refactoring](/sdk/miscellaneous/hub_and_scope_refactoring/), focusing on implementation details and expected features. The original document remains unchanged, offering additional historical context and migration strategies.