word_count

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds a small behavioral detail by specifying the return type (int), but this is also implied by the 'Returns' section. There is no additional context about edge cases, performance, or counting semantics beyond the basic function, so a 3 is appropriate given the annotation coverage.

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: the main action appears in the first sentence, the usage guidance is a single clear sentence, and the return type is given in a minimal 'Returns' block. Every sentence earns its place with no redundancy or filler.

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, parameterless tool with a provided output schema and comprehensive annotations, the description fully covers what an agent needs: what it does, when to use it, and what it returns. No additional information about errors or edge cases is necessary given the tool's simplicity.

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 tool has zero parameters, and the description provides a baseline of 4 per the rubric. The schema coverage is trivially 100% since there are no parameters to describe, and the description does not need to add parameter details. The 'Returns' section adds value by stating the output type, which is not captured in the empty schema.

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 a specific verb ('Return') and a clear resource ('total number of entries in the vocabulary'), and explicitly distinguishes itself from the sibling word_list by noting it should be used when only the count is needed. This makes the tool's purpose unambiguous and differentiates it without requiring schema inspection.

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 explicitly names the alternative (word_list) and the condition for choosing this tool ('when you only need the count'). This direct routing leaves no ambiguity about when to use word_count over its sibling.

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