feat(observability): Add OpenTelemetry GenAI Semantic Projection

[Mluckydwyer]

Overview

Add opt-in OpenTelemetry GenAI 1.37+ semantic-convention support to NeMo Relay’s existing OTLP exporter.

Generic OpenTelemetry remains the default, OpenInference behavior is unchanged, and no backend-specific transport or intake code is added.

• I confirm this contribution is my own work, or I have the right to submit it under this project's license.
• I searched existing issues and open pull requests, and this does not duplicate existing work.

Details

• Add a gen_ai projection for agent, LLM, tool, embedding, retrieval, and reranking scopes.
• Map available provider, model, token usage, message, tool, conversation, status, and error data to GenAI attributes while retaining nemo_relay.*
  correlation attributes.
• Preserve the existing exporter, transport, batching, and lifecycle implementation.
• Add configuration and API support across Rust, Python, Node.js, C FFI, and Go.
• Keep content capture disabled by default and emit sensitive content only from sanitized events when explicitly enabled.
• Add compatibility, privacy, configuration, binding, and exporter tests. There are no intentional breaking changes.

Validation passed: Rust formatting, Clippy, the serial Rust workspace suite, 35 focused OpenTelemetry tests, 536 Python tests, 266 Node.js tests, Go and FFI
suites, documentation checks, and the complete pre-commit suite.

Reviewer considerations:

• OpenTelemetry 1.37 has no first-class reranking operation, so Relay uses the documented rerank operation.
• The updated observability skill should receive a refreshed signature through /nvskills-ci.

Where should the reviewer start?

Start with crates/core/src/observability/otel.rs, the projection in otel_genai.rs, and the coverage in crates/core/tests/unit/observability/ otel_tests.rs.

Related Issues: (use one of the action keywords Closes / Fixes / Resolves / Relates to)

• Relates to: none

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[github-actions]

Fern docs preview: https://nvidia-preview-pull-request-490.docs.buildwithfern.com/nemo/relay (​https://nvidia-preview-pull-request-490.docs.buildwithfern.com/nemo/relay​)

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License Diff

Compared against origin/main.

Lockfile license changes

Lockfile License Changes

Rust

Added

• opentelemetry-semantic-conventions 0.31.0 (Apache-2.0)

Removed

• None

Updated/Changed

• None

Node

Added

• None

Removed

• None

Updated/Changed

• None

Python

Added

• None

Removed

• None

Updated/Changed

• None

Status output

[license-diff] selected languages: rust, node, python
[license-diff] generating current inventory
[license-diff] current: generating Rust inventory
[license-diff] current: Rust inventory complete (427 packages)
[license-diff] current: generating Node inventory
[license-diff] current: Node inventory complete (367 packages)
[license-diff] current: generating Python inventory
[license-diff] current: Python inventory complete (105 packages)
[license-diff] current inventory complete
[license-diff] checking out base ref origin/main into a temporary worktree
[license-diff] base: generating Rust inventory
[license-diff] base: Rust inventory complete (426 packages)
[license-diff] base: generating Node inventory
[license-diff] base: Node inventory complete (367 packages)
[license-diff] base: generating Python inventory
[license-diff] base: Python inventory complete (105 packages)
[license-diff] base inventory complete
[license-diff] removing temporary base worktree
[license-diff] comparing inventories
[license-diff] rendering Markdown output
[license-diff] done

[Mluckydwyer]

Local tests in e2e environments are still WIP.

[willkill07]

Some minor comments. Also happy to get this across the finish line for you.

[willkill07]

We can get rid of this and only keep with_options.

Although a breaking API change, we haven't stabalized the FFI/Go APIs yet.

[willkill07]

If we do keep generic and also add GenAI, why not just create a new OtelGenAISemanticConvention exporter type? That way we keep all existing behavior/APIs and introduce the new one:

1. as a new exporter type
2. as a new configuration option under the observability plugin

[willkill07]

This table supports my suggestion on splitting out as a new type rather than overload OpenTelemetry