Borrowing it
Nothing to install: this file belongs to ensemblr-hq/ensemblr. 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/ensemblr-hq/ensemblr/master/.agents/skills/fallow/SKILL.mdgit clone --depth 1 https://github.com/ensemblr-hq/ensemblrWrote 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/ensemblr-hq/ensemblr/fallow)<a href="https://agentmods.dev/skills/ensemblr-hq/ensemblr/fallow"><img src="https://agentmods.dev/badge/skills/ensemblr-hq/ensemblr/fallow/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/ensemblr-hq/ensemblr/fallow"><img src="https://agentmods.dev/badge/skills/ensemblr-hq/ensemblr/fallow.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 | $0.00178 | $0.09009 |
| Opus 5.5 | $0.00071 | $0.03604 |
| Sonnet 5.5 | $0.00036 | $0.01802 |
| Haiku 4.5 | $0.00018 | $0.00901 |
Grade C, and why
fallow scanned grade C with 1 finding 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.
Hidden instructionshighPrompt injection
Directives inside HTML comments, invisible characters or bidirectional overrides are read by the model and not by the person reviewing the file.
| `health` | Function complexity analysis (also covers Angular templates as synthetic `<template>` findings: external `.html` files via `templateUrl` AND inline `@Component({ template: \`...\` })` literals; suppress exte This is a copy
86% identical to fallow — 449 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 410 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Fallow: codebase intelligence for JavaScript and TypeScript
Codebase intelligence for JavaScript and TypeScript. The free static layer reports quality, changed-code risk, cleanup opportunities, circular dependencies, code duplication, complexity hotspots, architecture boundary violations, feature flag patterns, and opt-in security candidates. Runtime coverage merges production execution data into the same fallow health report for hot-path review, cold-path deletion confidence, and stale-flag evidence, with a single local capture available by default and continuous/cloud runtime monitoring available as an optional mode. 118 framework plugins, zero configuration, sub-second static analysis.
When to Use
- Finding cleanup opportunities (unused files, exports, types, enum/class members)
- Finding unused or unlisted dependencies
- Detecting code duplication and clones
- Checking code health and complexity hotspots
- Cleaning up a codebase before a release or refactor
- Auditing a project for structural issues
- Setting up CI quality gates or duplication thresholds
- Auto-fixing unused exports and dependencies
- Detecting feature flag patterns (environment gates, SDK calls, config objects)
- Investigating why a specific export or file appears unused
When NOT to Use
- Runtime error analysis or debugging
- Type checking (use
tscfor that) - Linting style or formatting issues (use ESLint, Biome, Prettier)
- Verified security vulnerability scanning or SAST.
fallow securitysurfaces local, deterministic security candidates for a downstream agent to verify; it does not prove exploitability. Use Snyk, CodeQL, or Semgrep for verified scanning, and an SCA tool for dependency CVEs. - Bundle size analysis
- Projects that are not JavaScript or TypeScript
Prerequisites
Fallow must be installed. If not available, install it:
npm install -g fallow # prebuilt binaries (fastest)
# or
npx fallow dead-code # run without installing
# or
cargo install fallow-cli # build from source
What ships with it
3 files 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 · 410 lines · 178 tokens per session scan C 7d48d4e64f7e
fallow is a skill published in the GitHub repository ensemblr-hq/ensemblr (8 stars, last pushed yesterday), licensed Apache-2.0. It adds 178 tokens to every session and 9,009 once invoked, about $0.0007 per session on Opus 5.5. A static security scan graded it C with 1 finding (hidden instructions). It is 86% identical to fallow, differing in 449 lines, and is treated as a copy.
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