Introduce opamp data model for agents, starting with identity

CHANGELOG.md

@@ -34,6 +34,13 @@
 
 #### Bugfixes
 
+### OpAMP Data Model
+
+#### Enhancements
+
+- Add initial data model for agent identify with OpAMP.
+  [#379](https://github.com/signalfx/gdi-specification/pull/379)
+
 ## [1.9.0] - 2026-04-07
 
 ### Configuration

README.md

@@ -16,6 +16,7 @@ The following specification sections are currently in scope:
 - [Semantic Conventions](specification/semantic_conventions.md)
 - [Repository](specification/repository.md)
 - [Versioning](specification/versioning.md)
+- [OpAMP Data Model](specification/opamp_datamodel.md)
 
 GDI repositories MUST adopt GDI specification changes by their next `MINOR` release
 and within three months (whichever is sooner). The GDI specification and GDI

specification/opamp_datamodel.md

@@ -0,0 +1,25 @@
+# OpAMP Data Model
+
+**Status**: [Experimental](../README.md#versioning-and-status-of-the-specification)
+
+This document describes data model fields used by *language agents*
+when configured to communicate with an OpAMP server. For more information
+about OpAMP, please see the
+[opamp-spec](https://github.com/open-telemetry/opamp-spec).
+
+## Identifying Attributes
+
+The `AgentDescription` message includes a set of
+[identifying attributes](https://github.com/open-telemetry/opamp-spec/blob/main/specification.md#agentdescriptionidentifying_attributes).
+
+This set of identifying attributes MUST be comprised, in its entirety,
+of the Agent's resource attributes. All detected or configured
+resource attributes MUST be present in the identifying attributes.
+The identifying attributes MUST NOT contain any other attributes
+that are not obtained from the current Resource.
+
+## Non-Identifying Attributes
+
+The `AgentDescription` message includes a set of
+[non-identifying attributes](https://github.com/open-telemetry/opamp-spec/blob/main/specification.md#agentdescriptionnon_identifying_attributes).
+Agents SHOULD NOT specify any non-identifying attributes.