Tool Gate · How it works
How the Tool-Input Schema Turnstile gate works
How the Tool-Input Schema Turnstile grades 12 parameters across 5 tools: a consequence gate marks any money, identity, or destructive parameter with a loose schema OPEN DOOR — which is how 3 open-door tools force UNGUARDED at 58% guard coverage.
How the gate works
This tool grades every tool your AI agent can call - graded per parameter against the guards its kind and consequence require. It reads 5 tools and rolls them into one verdict — the worst, never the average — and then a gate that can only make it worse.
The 5 tools
| Tool | Verdict |
|---|---|
| issue_refundfix first | OPEN DOOR3 params · weakest: amount - money param missing cross_field_rule |
| delete_records | OPEN DOOR2 params · weakest: filter - destructive param missing max |
| lookup_customer | OPEN DOOR2 params · weakest: email - identity param missing pattern |
| send_email | LOOSE2 params · weakest: recipient_count - missing max |
| issue_refund_v2 | LOOSE3 params · weakest: currency - required/optional not stated |
The verdict bands
A parameter whose consequence is money, identity, or destructive must declare every guard its kind requires. Miss one and it's OPEN DOOR (rank 2) instead of LOOSE (rank 1) - the same missing guard is judged harsher because of what the parameter can do, not how it's typed.
In the worked sample it reads UNGUARDED — 12 parameters across 5 tools, 7 fully typed. But 3 high-consequence parameters are missing a guard their consequence requires - issue_refund.amount (money, no cross_field_rule), delete_records.filter (destructive, no max), and lookup_customer.email (identity, no pattern) - and 2 more are only LOOSE. Guard coverage reads 58%, but coverage is context only: one open door on a money, identity, or destructive parameter is enough to make the whole registry UNGUARDED, worst-not-average. The one thing to fix first: issue_refund.amount - a money parameter with no cross_field_rule; nothing here can stop a refund larger than the order total..
Common questions
Can every tool look survivable on the How the Tool-Input Schema gate works and the company still read UNGUARDED?
Yes. The roll-up takes the worst of 5 tools — never the average — then a worsen-only gate, the Consequence gate gate, escalates when trouble clusters. In the worked sample it reads UNGUARDED because 12 parameters across 5 tools, 7 fully typed. But 3 high-consequence parameters are missing a guard their consequence requires - issue_refund.amount (money, no cross_field_rule), delete_records.filter (destructive, no max), and lookup_customer.email (identity, no pattern) - and 2 more are only LOOSE. Guard coverage reads 58%, but coverage is context only: one open door on a money, identity, or destructive parameter is enough to make the whole registry UNGUARDED, worst-not-average.
What is a worsen-only gate?
A dispositive rule that can only lower a verdict, never raise it. One fatal flaw overrides an otherwise-set of survivable lines, because a single disqualifying gap shouldn't hide behind an average of the healthy ones. The tool also names the one thing to fix first — here, "issue_refund.amount - a money parameter with no cross_field_rule; nothing here can stop a refund larger than the order total.".
Grades the parameter contracts you declare; it calls no tool and executes nothing. Not legal or security advice.
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<p style="font:14px/1.5 system-ui,sans-serif"><a href="https://redhub.ai/visuals/tool/tool-input-schema-turnstile">How the Tool-Input Schema Turnstile gate works</a> — by <a href="https://redhub.ai">RedHub AI</a>, the AI that tells you when to doubt it.</p>Image + link — a static picture for any blog
<a href="https://redhub.ai/visuals/tool/tool-input-schema-turnstile"><img src="https://redhub.ai/visuals/tool/tool-input-schema-turnstile-share.png" alt="Diagram of the Tool-Input Schema Turnstile: twelve parameters across five tools rolled up worst-not-average, a consequence gate, and the registry reading UNGUARDED at 58% coverage." width="760" loading="lazy" style="max-width:100%;height:auto;border-radius:16px"></a>
<p style="font:14px/1.5 system-ui,sans-serif"><a href="https://redhub.ai">RedHub AI</a> — the AI that tells you when to doubt it.</p>
This is how Tool-Input Schema Turnstile works. More diagrams in the Visual Field Guide.