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 catpilotai/catpilot-ai-guardrails --skill language-baselinegit clone --depth 1 https://github.com/catpilotai/catpilot-ai-guardrailsWrote 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/catpilotai/catpilot-ai-guardrails/language-baseline)<a href="https://agentmods.dev/skills/catpilotai/catpilot-ai-guardrails/language-baseline"><img src="https://agentmods.dev/badge/skills/catpilotai/catpilot-ai-guardrails/language-baseline/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/catpilotai/catpilot-ai-guardrails/language-baseline"><img src="https://agentmods.dev/badge/skills/catpilotai/catpilot-ai-guardrails/language-baseline.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 | $0.00115 | $0.04680 |
| Opus 5 | $0.00057 | $0.02340 |
| Sonnet 5 | $0.00023 | $0.00936 |
| Haiku 4.5 | $0.00012 | $0.00468 |
Grade B, and why
language-baseline scanned grade B with 3 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Cloud metadata endpointmediumServer-side request forgery
One request to 169.254.169.254 can return temporary IAM credentials.
fetches `http://169.254.169.254/latest/meta-data/` from the Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
`$(curl evil)` as a substitution. (Command injection — CWE-78.) Runs shell commandslowCapability
Expected in a hook, worth knowing in a rule or an instructions file.
`subprocess.call(..., shell=True)`, and the shell treats How it starts
The opening of the file, as written. The whole thing — 549 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Why
A small number of injection and arbitrary-code-execution patterns account for most of the application-layer CVEs published every year. The shape repeats across languages: a value the program did not produce reaches a context where it is interpreted as code.
- A user-supplied id reaches a SQL string by concatenation, and
the database treats the trailing
'; DROP TABLE ...as syntactically valid SQL. (SQL injection — CWE-89.) - A search term reaches a shell command via
subprocess.call(..., shell=True), and the shell treats$(curl evil)as a substitution. (Command injection — CWE-78.) - A user-supplied bio reaches the DOM via
innerHTML, and the browser parses the embedded<script>tag. (XSS — CWE-79.) - A user-supplied filename reaches
fs.readFile, and the OS resolves../../etc/passwd. (Path traversal — CWE-22.) - A user-supplied object reaches
pickle.loads, and Python instantiates whatever class the byte stream names — including one whose__reduce__runsos.system. (Insecure deserialization — CWE-502.) - A user-supplied URL reaches
requests.get, and the server fetcheshttp://169.254.169.254/latest/meta-data/from the cloud metadata service. (SSRF — CWE-918.)
The fix in every case has the same shape: treat external input as data, not as code, by routing it through an API designed for the context (parameterized query, argv-style exec, escaping sink, allowlist).
This skill is not language-specific; the same six classes are the same across Python, JavaScript/TypeScript, Ruby, Java, Go, PHP, and C#. The language-specific shape of each fix changes; the rule does not.
When to apply
Apply this skill before the agent writes, recommends, or commits any code that:
- Constructs a SQL query from values that are not literals in the source.
- Invokes a subprocess, shell, or system command with arguments that are not literals.
- Writes a value into the DOM, an HTML response body, or any HTML-template sink.
- Reads, writes, opens, deletes, or traverses a filesystem path derived from input.
- Deserializes data using a format that can construct arbitrary
types (
pickle,yaml.load,Marshal,ObjectInputStream,unserialize). - Executes a string as code (
eval,new Function,setTimeout(string),exec). - Bypasses the type system in a way that erases verification
(
as anyin TypeScript,@SuppressWarnings("unchecked")in Java,interface{}casts in Go without runtime checks). - Issues an outbound HTTP request to a URL the program did not fully construct.
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.
- 11d ago First seen · 549 lines · 115 tokens per session scan B 2739d0b76a92
language-baseline is a skill published in the GitHub repository catpilotai/catpilot-ai-guardrails (2 stars, last pushed 2mo ago), licensed MIT. It adds 115 tokens to every session and 4,680 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it B with 3 findings (cloud metadata endpoint, makes network calls, runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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