Borrowing it
Nothing to install: this file belongs to marcusrbrown/systematic. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/marcusrbrown/systematic/main/.agents/skills/running-with-without-evals/SKILL.mdgit clone --depth 1 https://github.com/marcusrbrown/systematicWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/marcusrbrown/systematic/running-with-without-evals)<a href="https://agentmods.dev/skills/marcusrbrown/systematic/running-with-without-evals"><img src="https://agentmods.dev/badge/skills/marcusrbrown/systematic/running-with-without-evals/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/marcusrbrown/systematic/running-with-without-evals"><img src="https://agentmods.dev/badge/skills/marcusrbrown/systematic/running-with-without-evals.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00057 | $0.01313 |
| Opus 5.5 | $0.00023 | $0.00525 |
| Sonnet 5.5 | $0.00011 | $0.00263 |
| Haiku 4.5 | $0.00006 | $0.00131 |
Grade A, and why
running-with-without-evals scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 70 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Running With/Without Evals
Overview
A with/without eval captures real opencode run transcripts on the same task, once with a plugin loaded and once without, to show what the plugin actually changes. The output is recorded sessions, not a benchmark.
Core principle: the result is only worth publishing if it would survive a hostile reader who has the transcripts. That means pre-registering the bar before you run, keeping a clean baseline, including the control that could disprove your thesis, and conceding what the baseline already does well.
The reusable harness lives at tests/manual/with-without-eval/run-arm.sh. Reuse it; don't reinvent the isolation.
When to use
- Building or refreshing the
with-without-systematicdemo page - Validating that a plugin/skill change actually moves model behavior
- Producing a credibility artifact for public promotion
When NOT to use
- You need statistical claims — this is n=1–3 recorded sessions, not a benchmark. Don't dress it up as one.
- The task is trivial (the baseline will look fine and the eval proves nothing)
The method
- Pre-register first. Write the task, the models, and the publishable-delta bar to a
PRE-REGISTRATION*.mdBEFORE any run. State the no-ship condition (if the bar isn't cleared, ship an honest decision guide, not a staged win). Committing this first is what lets you claim the result wasn't retrofitted. - Run each arm via
run-arm.sh <baseline|treatment> <model> <prompt-file> <out-dir> [seed-dir]. Baseline =--pure+ empty plugin array; treatment = plugin loaded. Use a paid model — free models rate-limit and the failure masquerades as empty output. - Verify the baseline is clean and the treatment loaded — the script checks
systematic_skillis absent (baseline) / present (treatment). A contaminated baseline is a dishonest demo. - Add the controls that matter (see below) before drawing conclusions.
- Have Oracle review the methodology and the drafted page before publishing. Council for the design if the matrix is non-trivial.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2mo ago First seen · 70 lines · 57 tokens per session scan A 374675e72129
running-with-without-evals is a skill published in the GitHub repository marcusrbrown/systematic (28 stars, last pushed today), licensed MIT. It adds 57 tokens to every session and 1,313 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
running-with-without-evals compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| running-with-without-evalsmarcusrbrown/systematic | Skill | 28 | today | MIT | A | 57 | Claude Code, Codex |
| plan-protocolkdcokenny/ocx | Skill | 980 | 1mo ago | MIT | A | 14 | Claude Code, Codex |
| plan-reviewkdcokenny/ocx | Skill | 980 | 1mo ago | MIT | A | 11 | Claude Code, Codex |
| opencode-ensemblehueyexe/opencode-ensemble | Skill | 254 | 18d ago | MIT | A | 42 | Claude Code, Codex |
| code-reviewkdcokenny/ocx | Skill | 980 | 1mo ago | MIT | A | 14 | Claude Code, Codex |
| code-philosophykdcokenny/ocx | Skill | 980 | 1mo ago | MIT | A | 32 | Claude Code, Codex |
| frontend-philosophykdcokenny/ocx | Skill | 980 | 1mo ago | MIT | A | 36 | Claude Code, Codex |