Log events reference

Every structured event the plugin can emit, exactly as named in hermes_otel.log_events.EVENTS. An event is an OTel log record with event_name set, emitted through Logger.emit on the plugin's own instrumentation scope (hermes_otel, version = the plugin version), never through the stdlib logging bridge. Events are off by default; logs.events.enabled: true turns them on, and they reach every log-capable backend and the dashboard's live store as long as one exists, with or without logs.capture. See Logs and events for the switches and the content rules.

What every event carries. The trace and span ids of the turn it belongs to (the enrichment processor records the tier as hermes.log.attribution: context), hermes.session_id and gen_ai.conversation.id, hermes.platform from the session root, the resource shared with spans and metrics, and the attributes listed below using the same names as the span the event mirrors (span attributes). Bodies are one display line. Secrets are redacted before any sink sees the record, like every other log record.

Content. Attributes marked content-gated carry prompt, response or tool content and are the only ones logs.events.content governs: full keeps what the span has, preview clips to preview_max_chars, off drops them, inherit (the default) follows content_capture. A backend's own logs: {events: {content: …}} may narrow them further for that backend only. Metadata attributes always travel.

Severity. Severity numbers follow the OTel bands (INFO 9, WARN 13, ERROR 17); the rule per event is stated in its section. hermes.tool.duration_s and hermes.turn.duration_s exist only on events (the spans carry the *_ms form); everything else is shared with the spans.

This page is generated from the code by scripts/gen_config_docs.py; tests/unit/test_config_surface.py fails when it drifts, and tests/unit/test_log_events_docs.py fails when a hook emits an event the catalogue does not list.

Events

`hermes.turn.start`

Emitted from pre_llm_call. Severity: INFO. Body: turn <n> started.

Attribute	Content-gated
`hermes.session_id`
`gen_ai.conversation.id`
`hermes.platform`
`gen_ai.request.model`
`gen_ai.provider.name`
`hermes.turn.number`

`hermes.turn.end`

Emitted from on_session_end. Severity: INFO; WARN when interrupted; ERROR when failed. Body: turn <n> <final_status>.

Attribute	Content-gated
`hermes.turn.number`
`hermes.turn.final_status`
`hermes.turn.exit_reason`
`hermes.turn.api_call_count`
`hermes.turn.tool_count`
`hermes.turn.tools`
`gen_ai.usage.input_tokens`
`gen_ai.usage.output_tokens`
`gen_ai.usage.cache_read.input_tokens`
`gen_ai.usage.reasoning.output_tokens`
`hermes.cost.usage`
`hermes.turn.duration_s`
`error.type`

`hermes.tool.call`

Emitted from post_tool_call. Severity: INFO; WARN when blocked or timed out; ERROR on error. Body: tool <name> <outcome>.

Attribute	Content-gated
`gen_ai.tool.name`
`gen_ai.tool.call.id`
`gen_ai.tool.type`
`hermes.tool.outcome`
`hermes.tool.decided_by`
`hermes.tool.duration_s`
`gen_ai.tool.call.arguments`	yes
`gen_ai.tool.call.result`	yes

`hermes.approval.decision`

Emitted from post_approval_response. Severity: INFO; WARN when denied or timed out. Body: approval <choice> for <tool>.

Attribute	Content-gated
`hermes.approval.choice`
`hermes.approval.granted`
`hermes.approval.decided_by`
`hermes.approval.surface`
`hermes.approval.timed_out`
`hermes.approval.duration_ms`
`gen_ai.tool.name`

`hermes.api.error`

Emitted from api_request_error. Severity: ERROR; WARN when retryable. Body: api error <error.type> from <provider>.

Attribute	Content-gated
`error.type`
`http.response.status_code`
`hermes.retryable`
`hermes.retry.count`
`gen_ai.request.model`
`gen_ai.provider.name`
`exception.type`
`exception.message`

`hermes.subagent.start`

Emitted from subagent_start. Severity: INFO. Body: sub-agent <role> started.

Attribute	Content-gated
`hermes.subagent.role`
`hermes.subagent.child_session_id`
`hermes.subagent.parent_session_id`
`hermes.subagent.goal`	yes

`hermes.subagent.stop`

Emitted from subagent_stop. Severity: INFO; ERROR when the sub-agent reports failure. Body: sub-agent <role> <status>.

Attribute	Content-gated
`hermes.subagent.role`
`hermes.subagent.status`
`hermes.subagent.duration_ms`
`hermes.subagent.child_session_id`
`hermes.subagent.parent_session_id`
`hermes.subagent.summary`	yes

`hermes.session.finalize`

Emitted from on_session_finalize / on_session_reset. Severity: INFO. Body: session <id> <finalized|reset> (<reason>): <n> turn(s).

Attribute	Content-gated
`hermes.session.turn_count`
`hermes.session.duration_s`
`hermes.session.finalize_reason / hermes.session.reset_reason`

`gen_ai.client.inference.operation.details`

Emitted from post_api_request. Severity: INFO. Body: <operation> <model> (<input>/<output> tokens).

Attribute	Content-gated
`gen_ai.operation.name`
`gen_ai.provider.name`
`gen_ai.request.model`
`gen_ai.response.model`
`gen_ai.response.id`
`gen_ai.response.finish_reasons`
`gen_ai.usage.input_tokens`
`gen_ai.usage.output_tokens`
`gen_ai.conversation.id`
`gen_ai.input.messages`	yes
`gen_ai.output.messages`	yes
`gen_ai.system_instructions`	yes

Events​

hermes.turn.start​

hermes.turn.end​

hermes.tool.call​

hermes.approval.decision​

hermes.api.error​

hermes.subagent.start​

hermes.subagent.stop​

hermes.session.finalize​

gen_ai.client.inference.operation.details​

See also​