Check whether a function is a Luau closure

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so 'Safety: read-only' and 'idempotency=read-only' are redundant restatements. The description does add genuinely new context — cost=medium, phase=observe, active-client prerequisite, and a fallback pointer to tool-schema on failure — which supports a 3 rather than lower.

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?

Purpose is front-loaded, but the body is a semicolon-separated metadata dump with visible filler ('Safety: read-only' duplicates the annotation) and internal jargon ('call islclosure', 'guarded metadata'). Adequate but not tight.

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 2-param, no-output-schema, heavily-annotated read-only predicate, the description covers prerequisites, phase, and cost. But 'Produces: structured-observation' is vague about the return (presumably a boolean) and nothing distinguishes this predicate from its siblings, leaving a real completeness 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 coverage is 100%, so both parameters are already documented in the schema. The description merely re-lists the signature without adding format, semantics, or validation detail beyond what the schema provides; this is the baseline 3.

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 title states a specific verb+resource ('Check whether a function is a Luau closure') and the description confirms the mechanism ('resolve a function and call islclosure'). However, it never differentiates from the many sibling predicates (is-c-closure, is-new-c-closure, is-executor-closure), so an agent cannot tell which closure check applies without opening schemas.

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?

It lists prerequisites ('Requires: active-client, resolved-target') but gives no guidance on when to choose this over is-c-closure, is-new-c-closure, or closure-capabilities. No exclusions, no alternative routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.