Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add leventilo/mobius --skill paper-diffgit clone --depth 1 https://github.com/leventilo/mobiusWrote 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/leventilo/mobius/paper-diff)<a href="https://agentmods.dev/skills/leventilo/mobius/paper-diff"><img src="https://agentmods.dev/badge/skills/leventilo/mobius/paper-diff/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/leventilo/mobius/paper-diff"><img src="https://agentmods.dev/badge/skills/leventilo/mobius/paper-diff.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00087 | $0.03804 |
| Opus 5.5 | $0.00035 | $0.01522 |
| Sonnet 5.5 | $0.00017 | $0.00761 |
| Haiku 4.5 | $0.00009 | $0.00380 |
Grade A, and why
paper-diff 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 — 233 lines — stays where its author put it; the contents beside it link to each section on GitHub.
paper-diff
1. Purpose and scope
This skill produces the user-facing comparison artifact between the figures of the source paper and the rendered output of a Mobius simulation. It is the visible evidence that the simulation reproduces the physics described in the paper. Its product backs the green "reproduces Figure 3" badge surfaced near the simulator and the side-by-side panel that opens when a user clicks the badge.
The skill runs after primitive-generator has emitted Python code, after the simulation has executed in the Claude Managed Agents sandbox, and after at least one frame per relevant figure has been exported. It runs before the orchestrator pitches the final assembled simulator. It does not run during the live slider loop; the diff is computed once per stable simulation snapshot and cached.
What this skill does NOT do. It does not extract figures from the paper PDF (that is paper-parser), does not decide whether to block the pipeline (that is science-integrity), does not render the side-by-side panels in the browser (that is viz-mapper), and does not invent ground-truth values.
2. Distinction from science-integrity.figure_diff
Load-bearing. Both skills compare images but serve orthogonal purposes.
science-integrity.figure_diff is one of the five deterministic integrity checks (units, CFL, conservation, figure-diff, claim-match). It returns pass | warn | fail, writes into simspec.integrity.checks[], and on fail blocks the pipeline so the orchestrator re-dispatches primitive-generator. It is silent on the user surface.
paper-diff is the user-facing report. It returns a rich structured object enumerating matched features, missing features, spurious features, color and axis agreement, and surviving numerical claims. It is always rendered in the UI and never blocks. Even on catastrophic disagreement, the simulator renders with a red "divergent" badge and a panel listing every divergence verbatim. The bet: an honest "this does not match Figure 3 because the simulation produced 2 peaks where the paper shows 4" is more valuable to a user and a judge than a silently downgraded match.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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 · 233 lines · 87 tokens per session scan A 576ac96e76ac
paper-diff is a skill published in the GitHub repository leventilo/mobius (8 stars, last pushed 6mo ago), licensed MIT. It adds 87 tokens to every session and 3,804 once invoked, about $0.0003 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 2026-08-31.
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