Skills/npm/fallow

fallow@3.42.0

CAUTION· install only

Publisher claims: "Codebase intelligence for TypeScript and JavaScript: health, complexity, duplication, architecture, styling drift, and unused code from one graph. CLI, LSP, and MCP server. Zero config for over 100 frameworks." Observed in sandbox: no network, touches nothing outside the project, writes no memory.

Registry npm (MCP server)Publisher fallow-rs · publishing for 242 daysInstalls 8.4MLast detonated 4d ago
What would fix thisWatchDispute verdict

Coverage

Nothing executable in the bundle ran; the trace covers the install step only.
Tested
every file read, file written and host contacted by what ran
Not tested
use of the skill by an agent

Is [email protected] safe to install?

KillerSkills ran it in the KillerSkills honeypot sandbox (1 scenario; nothing executable in the bundle ran; the trace covers the install step only) on 2026-11-10 and scored it 69/100 (Caution). It is not known to be malicious, but it has behaviour or code a security policy should decide on before install. Notable findings: Instructs the agent to modify its persistent memory or instruction files; HTML comment carrying imperative instructions to the agent. Summary: no network, touches nothing outside the project, writes no memory.

Behavior trace

Honeypot run · 0 s · 1 scenarios · 0 deviations
t+CategoryObserved action
0.0sprocessno install scripts in bundle
0.0sprocessscript backend runs setup only
0.0sprocessscript backend runs setup only
0.0sprocessno install scripts to re-run

Static findings

HIGH
Instructs the agent to modify its persistent memory or instruction filesskills/fallow/SKILL.md:69 · Instructs the agent to modify its persistent memory or instruction files…es: guard commits and PRs, baseline the existing backlog and clean by category, add AGENTS.md guidance, or keep as-is. Mutate only after consent. On decline, run `fallow ini…Fix: Remove the text that addresses the agent rather than the reader; describe behavior, do not instruct.
AST01
MEDIUM
File permission modification commandcapabilities.json:7862 · File permission modification command — agent changes file ownership/permissions"title": "World-writable chmod mode",Fix: Request the narrowest permission that works; replace wildcards with the exact paths or hosts.
AST05
CRITICAL
HTML comment carrying imperative instructions to the agentskills/fallow/references/cli-reference.md:78 · HTML comment carrying imperative instructions to the agentfallow-ignore-file complexityFix: Keep SKILL.md to visible, descriptive text. Remove comments and encoded text that address the agent.
AST01
MEDIUM
File type combined with upload actionskills/fallow/SKILL.md:294 · File type combined with upload action — agent may exfiltrate local data files…Script path aliases (e.g. `@myorg/*`) are declared only in a root `tsconfig.base.json` that the per-package `tsconfig.json` files do not extend, imports through those aliases do not resolve, so dead-code signals (unused files/exports, and …Fix: Remove the call, or declare the host in frontmatter and explain in the README what is sent and why.
AST07
MEDIUM
Process kill commandschema.json:2016 · Process kill command — agent can terminate processes…st run; individual pack rules opt up via `\"severity\": \"error\"`.\n`off` is a kill switch that disables the whole evaluator (per-rule\nseverity cannot resurrect it…Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
npx invocation of non-well-known packageskills/fallow-setup/SKILL.md:30 · npx invocation of non-well-known package — may execute untrusted code…tep 3, Fallow is not installed. Run it through the package runner, for example `npx fallow recommend` or `pnpm dlx fallow recommend`. After step 3, use the runner of the …Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
LOW
Unpinned dependencyscripts/verify-binary.js:452 · Unpinned dependency`platform package may be tampered with or incomplete. Reinstall with \`npm install fallow@latest\` ` +Fix: Pin the exact version (`[email protected]`, `==1.2.3`) so every install gets the bytes that were reviewed.
AST06
LOW
Unpinned dependencyscripts/verify-binary.js:610 · Unpinned dependency// actionable error pointing the user at `npm install fallow@latest` (sinceFix: Pin the exact version (`[email protected]`, `==1.2.3`) so every install gets the bytes that were reviewed.
AST06
LOW
Unpinned dependencyscripts/verify-binary.js:450 · Unpinned dependency`your project's package.json to >=2.77.0 (for example \`npm install fallow@latest\`).`Fix: Pin the exact version (`[email protected]`, `==1.2.3`) so every install gets the bytes that were reviewed.
AST06
LOW
Unpinned dependencyscripts/verify-binary.js:574 · Unpinned dependency// `npm install fallow@latest` (the embedded-digest fieldFix: Pin the exact version (`[email protected]`, `==1.2.3`) so every install gets the bytes that were reviewed.
AST06
LOW
Unpinned dependencyscripts/verify-binary.js:640 · Unpinned dependency`Run \`npm install fallow@latest\` to refresh, or set ${SKIP_ENV}=1 ` +Fix: Pin the exact version (`[email protected]`, `==1.2.3`) so every install gets the bytes that were reviewed.
AST06
MEDIUM
File type combined with upload actioncapabilities.json:2176 · File type combined with upload action — agent may exfiltrate local data files…al signs snapshot for trend tracking. Defaults to `.fallow/snapshots/{timestamp}.json` if no path is given. A given path must resolve inside the project root, its Git work tree, the CI workspace or a temp directory. Forces file-scores, hot…Fix: Remove the call, or declare the host in frontmatter and explain in the README what is sent and why.
AST07
MEDIUM
npx invocation of non-well-known packageskills/fallow/SKILL.md:39 · npx invocation of non-well-known package — may execute untrusted codenpx fallow dead-code # run without installingFix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
Process kill commandcapabilities.json:7405 · Process kill command — agent can terminate processes"DO_NOT_TRACK": "Honored as a top-precedence telemetry kill switch (consoledonottrack.com convention).",Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Process kill commandcapabilities.json:7402 · Process kill command — agent can terminate processes"FALLOW_TELEMETRY_DISABLED": "Admin/fleet kill switch: truthy values hard-disable telemetry and refuse fallow telemetry enable.",Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05

Cost to the agent

Instructions loaded
≈10,736 tok
2 files · 26 in bundle

Tokens estimated at four characters each. Skills load their instruction text when triggered; the figure is what that costs.

Known vulnerabilities

No advisories in OSV for fallow@3.42.0 as of 4d ago. This is the package itself, not its dependencies.

What would make this Verified

11 points to 80 · weights: behavior 45%, static 25%, prompt 15%, publisher 15%
  1. Text that tells the agent to ignore its instructions≈ +9 on the totalDelete phrases like "ignore previous instructions", "override", "bypass" from SKILL.md and tool descriptions. Describe what the skill does; do not instruct the agent about other rules.
  2. Unclaimed publisher≈ +8 on the totalClaim fallow-rs: a verified publisher gets +50 on publisher trust. It is free and usually instant with GitHub sign-in.
  3. Hidden instructions≈ +6 on the totalRemove HTML comments, zero-width characters and white-on-white text that carry instructions. Everything the agent is meant to read should be visible to the person reading the file.
  4. Unpinned dependencies≈ +4 on the totalPin exact versions (and ideally hashes) in package.json, requirements or the install script so the bundle cannot change under you.
  5. File permission modification command≈ +2 on the totalRequest the narrowest permission that works; replace wildcards with the exact paths or hosts.
  6. File type combined with upload action≈ +2 on the totalRemove the call, or declare the host in frontmatter and explain in the README what is sent and why.
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