nf-runinsights

Cross-run benchmarking for Nextflow. The plugin records per-process resource metrics for every run into a local history store, compares each new run against previous runs of the same pipeline, and reports what changed and why: regressions with likely causes, over-provisioned resources, retry storms, and pipeline-wide slowdowns.

Nextflow's built-in reports tell you everything about one run. nf-runinsights tells you how this run compares to every run before it.

Why not the built-in tools

Built-in artifacts also disappear with nextflow clean or a deleted work directory. The history store is independent and durable.

Requirements

• Nextflow 24.10.0 or later
• Java 17+ to build

Installation

Not yet on the plugin registry. From source:

git clone <this repo>
cd nf-runinsights
make install

Usage

Enable the plugin in your config:

plugins {
    id 'nf-runinsights@0.1.0'
}

Run your pipeline as usual. At the end of each run:

nf-runinsights: 3 prior run(s) of 'nf-core/sarek' in history
nf-runinsights: CRUNCH: 8.0s vs 2.0s median over 3 prior run(s), 4.0x slower
nf-runinsights: report: /path/to/launchdir/runinsights-report.md

The first run records a baseline; comparisons start on the second. The markdown report contains the findings plus a per-process table of this run against the historical medians.

The plugin is a pure observer. It never alters pipeline behavior, and any failure in insight generation is swallowed so it cannot fail a run.

Configuration

runinsights {
    // history store directory (default: ~/.nf-runinsights/history).
    // Point it at a shared directory or s3:// prefix so a whole team
    // contributes to one history. No server required.
    history = '/shared/projects/my-team/runinsights'

    // optional AI narration of the report, off by default
    ai {
        enabled = true
        model = 'claude-opus-5'
    }
}

What is recorded

One JSON file per run, containing per-process aggregates:

Only process names and statistics are stored. No file paths, sample identifiers, or pipeline outputs.

Findings

All findings are computed deterministically from recorded numbers:

• Regression: a process is at least 1.5x slower than its historical median and at least 2 seconds slower in absolute terms. Where the evidence supports it, a likely cause is attached: queue wait rather than execution, a container change, or input growth with flat throughput.
• Improvement: the mirror of the above.
• Environment: when most processes slow down together, one pipeline-wide finding points at the machine, cluster load, or storage instead of blaming individual tools.
• Over-provisioning: peak memory never exceeded 25% of the request across every recorded run of a process.
• Retries and failures.

The thresholds exist to keep sub-second scheduler jitter out of the findings.

History store

~/.nf-runinsights/history/
  20260817T145715-tender_mccarthy.json
  20260817T151009-admiring_kalam.json

A run file is created once and never appended, which makes the store safe for concurrent runs on shared filesystems and compatible with object storage. Paths resolve through Nextflow's filesystem layer, so history = 's3://bucket/prefix' works with the run's own credentials. A history.jsonl file from earlier plugin versions is still read, never written.

Dashboard

A local web UI over the store. Python standard library only:

pipx run nf-runinsights-dashboard   # http://localhost:8765

pipx run nf-runinsights-dashboard --history /shared/team/runinsights

From a repo checkout the old door still works, no install at all:

python3 dashboard/app.py

Pick runs, compare them side by side with deltas against a baseline, and optionally ask free-form questions. Ask needs the anthropic package (pipx run --spec 'nf-runinsights-dashboard[ask]' nf-runinsights-dashboard, or pip install anthropic from a checkout) and ANTHROPIC_API_KEY; everything else works without them.

MCP server

Exposes the history store to any MCP client: Claude Code, Claude Desktop, Gemini CLI, or an OpenAI agent. The server is read-only and contains no AI; the assistant that connects to it supplies the model.

pipx install 'nf-runinsights-dashboard[mcp]'
claude mcp add --scope user nf-runinsights -- ~/.local/bin/nf-runinsights-mcp

Use the absolute path: MCP clients spawn servers without your shell PATH. (From a repo checkout, pip install mcp and pointing the client at an absolute python3 plus mcp-server/server.py still works.)

Tools: list_runs, get_run, compare_runs, get_process_trend. Then ask your assistant things like "compare my last two sarek runs" or "why was last night's run slow".

nf-runinsights-mcp --selftest exercises every tool against the real store without an MCP client.

AI narration

With runinsights.ai.enabled = true and ANTHROPIC_API_KEY in the launch environment, the report gains an "AI analysis" section. The division of labor is strict: the engine computes every number and finding; the model only explains and prioritizes them, and is instructed never to invent values. The call is best-effort: missing credentials or any API failure leaves the deterministic report untouched.

Limitations

• The macOS local executor does not collect memory or CPU metrics; use Docker or a Linux executor for those columns.
• Tasks under a few seconds have noisy timings. The thresholds filter most of it, but treat sub-second deltas as noise.
• Failed or partial runs are recorded and can distort baselines. Check the process count before using a run as a comparison baseline.
• Local scripts are identified by filename, so two different pipelines both named main.nf share a history. Registered pipelines such as nf-core/sarek are unambiguous.

Development

make test        # unit tests
make install     # build and install into ~/.nextflow/plugins
cd test-pipeline && nextflow run main.nf          # record a baseline
cd test-pipeline && nextflow run main.nf --slow   # trigger a regression

The Python readers live in nf_runinsights/ and ship to PyPI as nf-runinsights-dashboard (python3 -m build, then twine upload). Keep its version in pyproject.toml in step with the plugin version.

License

Apache-2.0