launching-evals

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Run, monitor, analyze, and debug LLM evaluations via nemo-evaluator-launcher. Covers running evaluations, checking status and live progress, debugging failed runs, exporting artifacts and logs, and analyzing results. ALWAYS triggers on mentions of running evaluations, checking progress, debugging failed evals, analyzing or analysing runs or results, run directories or artifact paths on clusters, Slurm job issues, invocation IDs, or inspecting logs (client logs, server logs, SSH to cluster, tail logs, grep logs). Do NOT use for creating or modifying evaluation configs.

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NPX Install

npx skill4agent add nvidia/skills launching-evals

NeMo Evaluator Skill

Quick Reference

nemo-evaluator-launcher CLI

bash
# Run evaluation
uv run nemo-evaluator-launcher run --config <path.yaml>
uv run nemo-evaluator-launcher run --config <path.yaml> -t <a_single_task_to_be_run_by_name>
uv run nemo-evaluator-launcher run --config <path.yaml> -t <task_name_1> -t <task_name_2> ...
uv run nemo-evaluator-launcher run --config <path.yaml> -o evaluation.nemo_evaluator_config.config.params.limit_samples=10 ...

# Preview the resolved config and the sbatch script without running the evaluation
uv run nemo-evaluator-launcher run --config <path.yaml> --dry-run

# Check status (--json for machine-readable output)
uv run nemo-evaluator-launcher status <invocation_id> --json

# Get evaluation run info (output paths, slurm job IDs, cluster hostname, etc.)
uv run nemo-evaluator-launcher info <invocation_id>

# Copy just the logs (quick — good for debugging)
uv run nemo-evaluator-launcher info <invocation_id> --copy-logs ./evaluation-results/

# For artifacts: use `nel info` to discover paths. If remote, SSH to explore and rsync what you need.
# If local, just read directly from the paths shown by `nel info`.
# ssh <user>@<hostname> "ls <artifacts_path>/"
# rsync -avzP <user>@<hostname>:<artifacts_path>/{results.yml,eval_factory_metrics.json,config.yml} ./evaluation-results/<invocation_id>.<job_index>/artifacts/

# Resume a failed/interrupted run (re-sbatches existing run.sub in the original run directory)
uv run nemo-evaluator-launcher resume <invocation_id>

# List past runs
uv run nemo-evaluator-launcher ls runs --since 1d   

# List available evaluation tasks (by default, only shows tasks from the latest released containers)
uv run nemo-evaluator-launcher ls tasks
uv run nemo-evaluator-launcher ls tasks --from_container nvcr.io/nvidia/eval-factory/simple-evals:26.03

Workflow

The complete evaluation workflow is divided into the following steps you should follow IN ORDER.
  1. Create or modify a config using the
    nel-assistant
    skill. If the user provides a past run, use its
    config.yml
    artifact as a starting point.
  2. Run the evaluation. See
    references/run-evaluation.md
    when executing this step.
  3. Monitor progress (MANDATORY after every
    nel run
    )
    : poll status repeatedly until SUCCESS/FAILED. See
    references/check-progress.md
    .
  4. Post-run actions (when terminal state reached):
    1. When the evaluation status is
      SUCCESS
      , analyze the results. See
      references/analyze-results.md
      when executing this step.
    2. When the evaluation status is
      FAILED
      , debug the failed run. See
      references/debug-failed-runs.md
      when executing this step.

Key Facts

  • Benchmark-specific info learned during launching/analyzing evals should be added to
    references/benchmarks/
  • PPP = Slurm account (the
    account
    field in cluster_config.yaml). When the user says "change PPP to X", update the account value (e.g.,
    coreai_dlalgo_compeval
    coreai_dlalgo_llm
    ).
  • Slurm job pairs: NEL (nemo-evaluator-launcher) submits paired Slurm jobs — a RUNNING job + a PENDING restart job (for when the 4h walltime expires). Never cancel the pending restart jobs — they are expected and necessary.
  • HF cache requirement: For configs with
    HF_HUB_OFFLINE=1
    , models must be pre-downloaded to the HF cache on each cluster before launching. Before running a model on a new cluster, always ask the user if the model is already cached there. If not, on the cluster login node:
    python3 -m venv hf_cli && source hf_cli/bin/activate && pip install huggingface_hub
    then
    HF_HOME=/lustre/fsw/portfolios/coreai/users/<username>/cache/huggingface hf download <model>
    . Without this, vLLM will fail with
    LocalEntryNotFoundError
    .
  • data_parallel_size
    is per node
    :
    dp_size=1
    with
    num_nodes=8
    means 8 model instances total (one per node), load-balanced by haproxy. Do NOT interpret
    dp_size
    as the global replica count.
  • payload_modifier
    interceptor
    : The
    params_to_remove
    list (e.g.
    [max_tokens, max_completion_tokens]
    ) strips those fields from the outgoing payload, intentionally lifting output length limits so reasoning models can think as long as they need.
  • Auto-export git workaround: The export container (
    python:3.12-slim
    ) lacks
    git
    . When installing the launcher from a git URL, set
    auto_export.launcher_install_cmd
    to install git first (e.g.,
    apt-get update -qq && apt-get install -qq -y git && pip install "nemo-evaluator-launcher[all] @ git+...#subdirectory=packages/nemo-evaluator-launcher"
    ).
  • Do NOT use
    nemo-evaluator-launcher export --dest local
    — it only writes a summary JSON (
    processed_results.json
    ), it does NOT copy actual logs or artifacts despite accepting
    --copy_logs
    and
    --copy-artifacts
    flags.
    nel info --copy-artifacts
    works but copies everything (very slow for large benchmarks). Preferred approach: use
    nel info
    to discover paths — if local, read directly; if remote, SSH to explore and rsync only what you need. Note that
    nel info
    prints standard artifacts but benchmarks produce additional artifacts in subdirs — explore to find them.