Explain a PrufGate rule by passing the rule ID named in a finding: see what it catches, how to fix the issue, and how to record a false positive.
What a rule catches, how to fix it, and how to record a false positive. Pass the rule ID a finding names.
| Name | Required | Description | Default |
|---|---|---|---|
| rule | Yes | Rule ID, e.g. canned-error-fallback or test-skip-smuggling |
Changes observed during successful MCP inspections.
v1.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuine value by disclosing the payload's substance (what the rule catches, remediation steps, false-positive recording guidance), but says nothing about behavior on an unknown rule ID or the exact return shape.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two compact sentences: the first front-loads what the tool returns, the second tells the agent exactly what to pass. No filler, no restatement of the tool name.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a read-only, single-parameter, idempotent lookup with full schema coverage and no output schema, the description covers purpose, input source, and output content. The only gap is edge-case behavior for an unrecognized rule ID, which is minor at this complexity.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 100% and the schema already gives example rule IDs, so the baseline is 3. The description earns above baseline by explaining where the value comes from — the rule ID a finding names — which tells the agent how to source the parameter rather than just its type.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states the resource concretely — a rule ID is explained in terms of what it catches and how to fix it — and adds the false-positive recording angle. It doesn't explicitly name or contrast the sibling scan/check tools, so differentiation is inferred from the resource ('rule' vs. scans/findings) rather than stated.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
'Pass the rule ID a finding names' gives a clear trigger condition: use this when a finding references a rule you need to understand or remediate. There are no explicit when-not cases or named alternatives, but for a single-purpose lookup tool the usage context is unambiguous.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.