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 laurigates/claude-plugins --skill probe-input-integritygit clone --depth 1 https://github.com/laurigates/claude-pluginsWrote 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/laurigates/claude-plugins/probe-input-integrity)<a href="https://agentmods.dev/skills/laurigates/claude-plugins/probe-input-integrity"><img src="https://agentmods.dev/badge/skills/laurigates/claude-plugins/probe-input-integrity/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/laurigates/claude-plugins/probe-input-integrity"><img src="https://agentmods.dev/badge/skills/laurigates/claude-plugins/probe-input-integrity.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 | $0.00047 | $0.02009 |
| Opus 5.5 | $0.00019 | $0.00804 |
| Sonnet 5.5 | $0.00009 | $0.00402 |
| Haiku 4.5 | $0.00005 | $0.00201 |
Grade A, and why
probe-input-integrity scanned grade A 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 22d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
allowed-tools: Read, Glob, Grep, Bash(gh *), Bash(curl *), Bash(sed *), Bash(chmod *), Bash(ls *), Bash(command *), TodoWrite How it starts
The opening of the file, as written. The whole thing — 154 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Probe Input Integrity — Never Fabricate an Identifier You're About to Test Against
Promoted from the always-loaded ~/.claude/rules/never-fabricate-test-identifiers.md
rule, whose stub keeps the gate lines. The body below is that rule's text.
When probing a system — an API endpoint, a URL, a record id, a file path, a ticket number — obtain the identifier from the system itself. Never invent a plausible-looking one. A fabricated identifier turns every subsequent observation into a two-variable experiment ("is the endpoint blocking me, or does this thing simply not exist?"), and the two failure modes are routinely indistinguishable in the response.
When to Use This Skill
| Use this skill when... | Use something else when... |
|---|---|
| About to probe an endpoint, URL, record id, path or ticket number | An empty search result is about to gate an action → tool-result-traps |
| Building a harness around code that is awkward to run directly | A named entity in an error may be a zero/default sentinel → code-quality-plugin:debugging-methodology |
Stubbing a CLI on PATH for a local test |
Verifying premises before a wave dispatch → verify-before-plan |
| Your own target set is empty, so a sweep would be green by construction |
The trap
The fabricated value looks real, so it never gets questioned. Its failure then gets attributed to the hypothesis actually under test.
Canonical break (2026-07, a research repo): investigating whether Reddit's
.jsonendpoint still worked, I made up a thread URL —/r/LocalLLaMA/comments/1i6r9rp/deepseek_r1_is_now_available_on_azure— a plausible id and slug, entirely invented. It returned403 Blocked, as did two further probes against the same fake thread. I reported the endpoint as IP-blocked. The user said "it works in my browser," and the first successful request revealed the truth: the endpoint returned a JSON 404 — the thread had never existed. The real discriminator was the client fingerprint, not the IP, and three "conclusive" probes had been testing a nonexistent resource.
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.
- 22d ago First seen · 154 lines · 47 tokens per session scan A e61f209ebbef
probe-input-integrity is a skill published in the GitHub repository laurigates/claude-plugins (60 stars, last pushed yesterday), licensed MIT. It adds 47 tokens to every session and 2,009 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-25.
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