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

The description accurately states the behavior: capitalizing only the first letter. No annotations exist, so the description carries the burden. It is clear but could mention that the rest of the text remains unchanged.

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 a single, well-structured sentence that is front-loaded with key information. No redundant or unnecessary words.

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 string operation, the description is nearly complete. However, it does not mention the return type; an agent might infer it returns a string, but explicit confirmation would be better.

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% with the parameter description 'Text to capitalize'. The tool description adds no additional meaning beyond what the schema already provides, so baseline score is appropriate.

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 'Capitalize first letter only' clearly states the action (capitalize) and the resource (first letter), and the specification 'only' distinguishes it from other case transformations like uppercase or title case.

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?

No explicit guidance on when to use this tool versus alternatives like 'capitalize' or 'uppercase'. While the simplicity implies use for single-character capitalization, the lack of context makes it less helpful for an agent to choose correctly.

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