Semantic conventionsv1.39.0

12 Jan 2026since v1.38.0

0 breaking31 notable134 editorial

From the upstream release notes

rpc: Rename rpc.client|server.duration to rpc.client|server.call.duration, change RPC duration metrics from milliseconds to seconds, and clarify metric and span duration semantics for streaming. (#383, #2961)
rpc: Rename rpc.grpc.request.metadata and rpc.connect_rpc.request.metadata to rpc.request.metadata
rpc.grpc.response.metadata and rpc.connect_rpc.response.metadata to rpc.response.metadata
rpc: Merge rpc.method and rpc.service into fully-qualified rpc.method attribute. Clarify how to handle possible high cardinality of rpc.method in edge cases. Clarify rpc.method usage in span names. (#2863, #3196, #3223)
rpc: Deprecate rpc.grpc.status_code, rpc.connect_rpc.error_code and rpc.jsonrpc.error_code attributes in favor of the more general rpc.response.status_code attribute.
rpc: Align RPC conventions with naming guidelines. Renames:
system, linux: Rename *.linux.memory metrics and attributes to *.memory.linux
peer: The peer.service attribute has been deprecated in favor of service.peer.name.
process: Introduce process.unix.file_descriptor.count and process.windows.handle.count metrics.
cloud: Add gcp.agent_engine as a value for cloud.platform

Read the full release notes

Notable31

removedsignalspan.rpc.clientRemoved from the registry (was development).
removedsignalspan.rpc.connect_rpc.clientRemoved from the registry (was development).
removedsignalspan.rpc.connect_rpc.serverRemoved from the registry (was development).
removedsignalspan.rpc.grpc.clientRemoved from the registry (was development).
removedsignalspan.rpc.grpc.serverRemoved from the registry (was development).
removedsignalspan.rpc.jsonrpc.clientRemoved from the registry (was development).
removedsignalspan.rpc.jsonrpc.serverRemoved from the registry (was development).
removedsignalspan.rpc.serverRemoved from the registry (was development).
renamedattributelinux.memory.slab.stateRenamed to system.memory.linux.slab.state.
renamedattributepeer.serviceRenamed to service.peer.name.
renamedmetricprocess.open_file_descriptor.countRenamed to process.unix.file_descriptor.count.
renamedattributerpc.connect_rpc.error_codeRenamed to rpc.response.status_code.
renamedattributerpc.connect_rpc.request.metadataRenamed to rpc.request.metadata.
renamedattributerpc.connect_rpc.response.metadataRenamed to rpc.response.metadata.
renamedattributerpc.grpc.request.metadataRenamed to rpc.request.metadata.
renamedattributerpc.grpc.response.metadataRenamed to rpc.response.metadata.
renamedattributerpc.jsonrpc.request_idRenamed to jsonrpc.request.id.
renamedattributerpc.jsonrpc.versionRenamed to jsonrpc.protocol.version.
renamedattributerpc.systemRenamed to rpc.system.name.
renamedmetricsystem.linux.memory.availableRenamed to system.memory.linux.available.
renamedmetricsystem.linux.memory.slab.usageRenamed to system.memory.linux.slab.usage.
deprecatedmetricrpc.client.durationReplaced by rpc.client.call.duration with unit s.
deprecatedattributerpc.grpc.status_codeUse string representation of the gRPC status code on the rpc.response.status_code attribute.
deprecatedattributerpc.jsonrpc.error_codeUse string representation of the error code on the rpc.response.status_code attribute.
deprecatedattributerpc.jsonrpc.error_messageUse the span status description or error.message attribute on other signals.
deprecatedmetricrpc.server.durationReplaced by rpc.server.call.duration with unit s.
deprecatedattributerpc.serviceValue should be included in rpc.method which is expected to be a fully-qualified name.
unitmetricsystem.linux.memory.availableUnit changed from By to {packet}.
unitmetricsystem.linux.memory.slab.usageUnit changed from By to {packet}.
instrumentmetricsystem.linux.memory.availableInstrument changed from updowncounter to counter.
instrumentmetricsystem.linux.memory.slab.usageInstrument changed from updowncounter to counter.

Editorial134

stabilityattributecontainer.idStability label respelled from development to alpha.
stabilityattributecontainer.image.nameStability label respelled from development to alpha.
stabilityattributecontainer.image.repo_digestsStability label respelled from development to alpha.
stabilityattributecontainer.image.tagsStability label respelled from development to alpha.
stabilityattributek8s.cluster.nameStability label respelled from development to alpha.
stabilityattributek8s.cluster.uidStability label respelled from development to alpha.
stabilityattributek8s.container.nameStability label respelled from development to alpha.
stabilityattributek8s.container.restart_countStability label respelled from development to alpha.
stabilityattributek8s.cronjob.annotationStability label respelled from development to alpha.
stabilityattributek8s.cronjob.labelStability label respelled from development to alpha.
stabilityattributek8s.cronjob.nameStability label respelled from development to alpha.
stabilityattributek8s.cronjob.uidStability label respelled from development to alpha.
stabilityattributek8s.daemonset.annotationStability label respelled from development to alpha.
stabilityattributek8s.daemonset.labelStability label respelled from development to alpha.
stabilityattributek8s.daemonset.nameStability label respelled from development to alpha.
stabilityattributek8s.daemonset.uidStability label respelled from development to alpha.
stabilityattributek8s.deployment.annotationStability label respelled from development to alpha.
stabilityattributek8s.deployment.labelStability label respelled from development to alpha.
stabilityattributek8s.deployment.nameStability label respelled from development to alpha.
stabilityattributek8s.deployment.uidStability label respelled from development to alpha.
stabilityattributek8s.job.annotationStability label respelled from development to alpha.
stabilityattributek8s.job.labelStability label respelled from development to alpha.
stabilityattributek8s.job.nameStability label respelled from development to alpha.
stabilityattributek8s.job.uidStability label respelled from development to alpha.
stabilityattributek8s.namespace.annotationStability label respelled from development to alpha.
stabilityattributek8s.namespace.labelStability label respelled from development to alpha.
stabilityattributek8s.namespace.nameStability label respelled from development to alpha.
stabilityattributek8s.node.annotationStability label respelled from development to alpha.
stabilityattributek8s.node.labelStability label respelled from development to alpha.
stabilityattributek8s.node.nameStability label respelled from development to alpha.
stabilityattributek8s.node.uidStability label respelled from development to alpha.
stabilityattributek8s.pod.annotationStability label respelled from development to alpha.
stabilityattributek8s.pod.labelStability label respelled from development to alpha.
stabilityattributek8s.pod.nameStability label respelled from development to alpha.
stabilityattributek8s.pod.uidStability label respelled from development to alpha.
stabilityattributek8s.replicaset.annotationStability label respelled from development to alpha.
stabilityattributek8s.replicaset.labelStability label respelled from development to alpha.
stabilityattributek8s.replicaset.nameStability label respelled from development to alpha.
stabilityattributek8s.replicaset.uidStability label respelled from development to alpha.
stabilityattributek8s.statefulset.annotationStability label respelled from development to alpha.
stabilityattributek8s.statefulset.labelStability label respelled from development to alpha.
stabilityattributek8s.statefulset.nameStability label respelled from development to alpha.
stabilityattributek8s.statefulset.uidStability label respelled from development to alpha.
enumattributecloud.platformEnum members changed (37 to 41).
enumattributecloud.providerEnum members changed (8 to 11).
addedsignalentity.service.instanceA unique instance of a logical service.
addedsignalentity.service.namespaceGroups related services that compose a system or application under a common namespace.
addedattributegen_ai.prompt.nameThe name of the prompt that uniquely identifies it.
addedattributejsonrpc.protocol.versionProtocol version, as specified in the jsonrpc property of the request and its corresponding response.
addedattributejsonrpc.request.idA string representation of the id property of the request and its corresponding response.
addedattributek8s.pod.hostnameSpecifies the hostname of the Pod.
addedattributek8s.pod.ipIP address allocated to the Pod.
addedattributek8s.pod.start_timeThe start timestamp of the Pod.
addedmetricmcp.client.operation.durationThe duration of the MCP request or notification as observed on the sender from the time it was sent until the response or ack is received.
addedmetricmcp.client.session.durationThe duration of the MCP session as observed on the MCP client.
addedattributemcp.method.nameThe name of the request or notification method.
addedattributemcp.protocol.versionThe version of the Model Context Protocol used.
addedattributemcp.resource.uriThe value of the resource uri.
addedmetricmcp.server.operation.durationMCP request or notification duration as observed on the receiver from the time it was received until the result or ack is sent.
addedmetricmcp.server.session.durationThe duration of the MCP session as observed on the MCP server.
addedattributemcp.session.idIdentifies MCP session.
addedattributeotel.event.nameIdentifies the class / type of event.
addedattributepprof.profile.doc_urlDocumentation link for this profile type.
addedattributepprof.profile.drop_framesFrames with Function.function_name fully matching the regexp will be dropped from the samples, along with their successors.
addedattributepprof.profile.keep_framesFrames with Function.function_name fully matching the regexp will be kept, even if it matches drop_frames.
addedmetricprocess.unix.file_descriptor.countNumber of unix file descriptors in use by the process.
addedmetricprocess.windows.handle.countNumber of handles held by the process.
addedmetricrpc.client.call.durationMeasures the duration of outbound remote procedure calls (RPC).
addedattributerpc.method_originalThe original name of the method used by the client.
addedattributerpc.request.metadataRPC request metadata, <key> being the normalized RPC metadata key (lowercase), the value being the metadata values.
addedattributerpc.response.metadataRPC response metadata, <key> being the normalized RPC metadata key (lowercase), the value being the metadata values.
addedattributerpc.response.status_codeStatus code of the RPC returned by the RPC server or generated by the client
addedmetricrpc.server.call.durationMeasures the duration of inbound remote procedure calls (RPC).
addedattributerpc.system.nameThe Remote Procedure Call (RPC) system.
addedattributeservice.peer.nameLogical name of the service on the other side of the connection. SHOULD be equal to the actual service.name resource attr...
addedattributeservice.peer.namespaceLogical namespace of the service on the other side of the connection. SHOULD be equal to the actual service.namespace res...
addedsignalspan.mcp.clientThis span describes the MCP call from the client side.
addedsignalspan.mcp.serverThis span describes the processing of the MCP request or notification initiated by the peer.
addedsignalspan.rpc.call.clientThis span represents an outgoing Remote Procedure Call (RPC).
addedsignalspan.rpc.call.serverThis span represents an incoming Remote Procedure Call (RPC).
addedsignalspan.rpc.connect_rpc.call.clientThis span represents an outgoing Remote Procedure Call (RPC).
addedsignalspan.rpc.connect_rpc.call.serverThis span represents an incoming Remote Procedure Call (RPC).
addedsignalspan.rpc.grpc.call.clientThis span represents an outgoing Remote Procedure Call (RPC).
addedsignalspan.rpc.grpc.call.serverThis span represents an incoming Remote Procedure Call (RPC).
addedsignalspan.rpc.jsonrpc.call.clientThis span represents an outgoing Remote Procedure Call (RPC).
addedsignalspan.rpc.jsonrpc.call.serverThis span represents an incoming Remote Procedure Call (RPC).
addedmetricsystem.memory.linux.availableAn estimate of how much memory is available for starting new applications, without causing swapping.
addedattributesystem.memory.linux.slab.stateThe Linux Slab memory state
addedmetricsystem.memory.linux.slab.usageReports the memory used by the Linux kernel for managing caches of frequently used objects.
guidanceattributecontainer.image.idGuidance note changed.
guidanceattributecontainer.image.repo_digestsGuidance note changed.
guidanceattributedb.query.summaryGuidance note changed.
guidanceattributedb.query.textGuidance note changed.
guidancesignalentity.serviceGuidance note changed.
guidanceattributeerror.typeGuidance note changed.
guidancesignalevent.rpc.messageGuidance note changed.
guidanceattributerpc.connect_rpc.request.metadataGuidance note changed.
guidanceattributerpc.connect_rpc.response.metadataGuidance note changed.
guidanceattributerpc.grpc.request.metadataGuidance note changed.
guidanceattributerpc.grpc.response.metadataGuidance note changed.
guidanceattributerpc.methodGuidance note changed.
guidancesignalspan.azure.cosmosdb.clientGuidance note changed.
guidancesignalspan.db.cassandra.clientGuidance note changed.
guidancesignalspan.db.clientGuidance note changed.
guidancesignalspan.db.couchdb.clientGuidance note changed.
guidancesignalspan.db.elasticsearch.clientGuidance note changed.
guidancesignalspan.db.hbase.clientGuidance note changed.
guidancesignalspan.db.mongodb.clientGuidance note changed.
guidancesignalspan.db.redis.clientGuidance note changed.
guidancesignalspan.db.sql.clientGuidance note changed.
guidancesignalspan.gen_ai.execute_tool.internalGuidance note changed.
guidancesignalspan.gen_ai.invoke_agent.clientGuidance note changed.
guidancemetricsystem.linux.memory.availableGuidance note changed.
guidancemetricsystem.linux.memory.slab.usageGuidance note changed.
guidanceattributethread.idGuidance note changed.
guidanceattributethread.nameGuidance note changed.
guidanceattributeuser_agent.nameGuidance note changed.
guidanceattributeuser_agent.versionGuidance note changed.
wordingattributecontainer.image.tagsContainer image tags. An example can be found in [Docker Image Inspect](https://docs.docker.com/reference/api/engine/version/v1.52/#tag/Image/operation/ImageIn...
wordingmetricdotnet.gc.heap.total_allocatedThe _approximate_ number of bytes allocated on the managed GC heap since the process has started. The returned value does not include any native allocations.
wordingmetricprocess.open_file_descriptor.countDeprecated, use process.unix.file_descriptor.count instead.
wordingmetricrpc.client.durationDeprecated, use rpc.client.call.duration instead. Note: the unit also changed from ms to s.
wordingattributerpc.connect_rpc.error_codeDeprecated, use rpc.response.status_code attribute instead.
wordingattributerpc.grpc.status_codeDeprecated, use string representation on the rpc.response.status_code attribute instead.
wordingattributerpc.jsonrpc.error_codeDeprecated, use string representation on the rpc.response.status_code attribute instead.
wordingattributerpc.jsonrpc.error_messageDeprecated, use span status description or error.message attribute on other signals.
wordingattributerpc.jsonrpc.request_idDeprecated, use jsonrpc.request.id instead.
wordingattributerpc.jsonrpc.versionDeprecated, use jsonrpc.protocol.version instead.
wordingmetricrpc.server.durationDeprecated, use rpc.server.call.duration instead. Note: the unit also changed from ms to s.
wordingattributerpc.serviceDeprecated, use fully-qualified rpc.method instead.
wordingattributerpc.systemDeprecated, use rpc.system.name attribute instead.
wordingattributeservice.versionThe version string of the service component. The format is not defined by these conventions.
wordingsignalspan.db.mariadb.clientSpans representing calls to MariaDB adhere to the general Semantic Conventions for Database Client Spans.
examplesattributerpc.methodExamples changed.