count_objects

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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description only restates 'read-only' without adding behavioral detail beyond the count/filter semantics. It does not describe return format or edge cases, but for a simple read-only count tool the existing annotations carry the main safety burden.

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?

The description is compact and front-loaded: it states the operation, the optional filter, and the read-only nature in two short bilingual sentences. Everything present is relevant, and there is no unnecessary elaboration.

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 simple tool with one optional documented parameter and safety annotations, the description is sufficiently complete. It defines what is counted and how to filter, and the operation name makes the numeric return type obvious. It does not explicitly state the return format, but that gap is minor here.

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?

The input schema already covers the parameter fully, including optionality and examples such as GeometryClass and Shape (100% schema coverage). The description does not add meaning beyond what the schema provides, so the baseline score of 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?

The description clearly states a specific verb ('count'), a specific resource ('scene objects'), and the optional superclass filter. This naturally distinguishes it from sibling tools like list_objects, find_objects, and select_by_superclass, and the explicit 'read-only' note reinforces its non-mutating role.

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 description conveys when to use the tool: when you need a count of scene objects, optionally filtered by superclass. However, it does not mention alternatives or exclusions, such as preferring list_objects for enumeration or select_by_superclass for selection. Usage guidance is 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.