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

"Query discarded" is a useful disclosure that the input is not retained, which is important given no annotations are present. However, the description does not clarify that the tool only counts characters and takes no other action, especially when schema fields suggest shape checks, normalization, or validation behavior.

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 very short and front-loaded, with no filler or redundancy. Both sentences earn their place, though the brevity contributes to the missing mapping between the description and the schema.

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 7-parameter tool with domain-specific schema fields and no output schema, two sentences are insufficient. The agent lacks the information needed to invoke the tool correctly, including which field represents the search query and what the count behavior actually applies to.

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 schema descriptions cover each parameter, but the description refers to a "search query" that does not exist as a schema property. An agent cannot determine which of ref, url, city, feed, host, json, or path should be populated, so the description adds confusion rather than parameter clarity.

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?

"Count characters in a search query" is a specific verb and object, but it does not map to any parameter in the input schema—there is no `query` field. The description also does not distinguish it from the many sibling tools, leaving the agent to guess the intended resource.

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 guidance is given on when to use this tool instead of siblings like validate-json, normalize-url, or web-fetch. There are no conditions, exclusions, or mention of alternatives.

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