Check whether a planned tool call and its arguments comply with security policy before execution, preventing unauthorized or risky agent actions.
Pre-flight permission evaluator enabling autonomous agents to check whether an intended action complies with security policy before execution.
| Name | Required | Description | Default |
|---|---|---|---|
| args | Yes | Arguments payload to validate against security rules | |
| tool | Yes | Target tool name to evaluate |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It usefully discloses that this is a non-executing evaluator ('pre-flight', 'before execution'), which implies no side effects. It says nothing about verdict semantics, whether the policy source is fixed, or what occurs on violation.
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?
A single tight sentence that front-loads the core purpose. Slightly jargon-heavy ('enabling autonomous agents') but every clause earns its place and nothing is redundant.
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?
There is no output schema and no annotations, so the description must explain the return/verdict behavior of a decision tool – allow, deny, reasons, or errors – and it does not. For a tool whose entire value is the evaluation result, this is a meaningful gap.
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 description coverage is 100% – both 'tool' and 'args' are documented in the schema. The description adds no syntax, format, or nesting detail for the nested 'args' payload beyond what the schema already provides, so baseline 3 applies.
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?
States a specific verb (evaluate/check) and resource (security policy compliance for an intended action), and the 'pre-flight ... before execution' framing implies a non-executing check. However, it never names or distinguishes itself from siblings like sentinel_safe_exec, so an agent must infer the boundary.
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?
The phrase 'before execution' implies usage timing, and the pre-flight evaluator framing suggests calling it prior to a mutating action. It stops short of naming when-not-to-use or routing to an alternative sibling such as sentinel_safe_exec, so guidance remains implied rather than explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.