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 batteryshark/rekit --skill js-sourcemap-extractgit clone --depth 1 https://github.com/batteryshark/rekitWrote 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/batteryshark/rekit/js-sourcemap-extract)<a href="https://agentmods.dev/skills/batteryshark/rekit/js-sourcemap-extract"><img src="https://agentmods.dev/badge/skills/batteryshark/rekit/js-sourcemap-extract/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/batteryshark/rekit/js-sourcemap-extract"><img src="https://agentmods.dev/badge/skills/batteryshark/rekit/js-sourcemap-extract.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 | $0.00089 | $0.00492 |
| Opus 5.5 | $0.00036 | $0.00197 |
| Sonnet 5.5 | $0.00018 | $0.00098 |
| Haiku 4.5 | $0.00009 | $0.00049 |
Grade A, and why
js-sourcemap-extract 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 1mo 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.
What it actually says
JS Source-Map Extractor
Recover the original source from a JavaScript source map — the fastest way to
turn a minified/bundled .js back into readable files, when a map is available.
When to use
You have a minified or webpacked bundle (or a leaked prod build) and there's a source
map — a .map file, or a //# sourceMappingURL= in the .js (inline data: map or
a sibling .map). A map's sourcesContent usually holds the complete original
source of every input file, so this beats deobfuscation: no guessing, you get the
author's actual code. If there's no map, fall back to js-deobfuscate.
What it does
- Loads the map from a
.map(JSON) or from a.js'ssourceMappingURL(inline base64data:map, or a sibling.mapfile — never fetched over the network). - Writes each
sourcesContententry tooutdir/<source-path>, cleaning the path (stripswebpack://, schemes, and../so everything stays under the output dir). - Reports how many sources were recovered vs. had no embedded content.
Read-only, pure stdlib. Then scan the recovered tree with js-covert-scan /
js-deobfuscate.
Usage
rekit run js-sourcemap-extract ./app.min.js.map ./out
rekit run js-sourcemap-extract ./bundle.js ./out # follows its sourceMappingURL
No map found → {"hasSourceMap": false, "note": "…"}.
Prerequisites
- python3 ≥ 3.8 — pure stdlib, nothing to vendor.
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.
- 1mo ago First seen · 42 lines · 89 tokens per session scan A 6b5dc3473689
js-sourcemap-extract is a skill published in the GitHub repository batteryshark/rekit (20 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 89 tokens to every session and 492 once invoked, about $0.0004 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.
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