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

The phrase 'Query discarded' adds a useful side-effect disclosure, which matters because no annotations are present. However, the description does not state the return format, error behavior, or whether character counting is Unicode-aware, and the mismatch between 'search query' and the schema parameters obscures what behavior the tool actually performs.

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 short and the first sentence is front-loaded with the intended action, while the second sentence addresses side effects. But the brevity comes at the cost of essential parameter information, so the sentences do not provide enough substance to be considered well-structured for tool use.

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?

Given a complex seven-property input schema and no output schema, the definition is severely incomplete. It does not explain which input field represents the 'search query,' what the count result looks like, or how this tool relates to the many sibling validation and formatting tools.

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 documents each property individually, but none is described as a search query and the description never maps the tool's central notion of a 'query' to any of the seven parameters. With seven plausible string inputs and no connection to the described behavior, an agent cannot determine which argument to pass.

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 clear verb and object ('Count characters in a search query') and notes that the input is discarded, but this is largely a restatement of the tool name. More importantly, the input schema contains no 'query' property—only ref, url, city, feed, host, json, and path—so the actual input resource is unclear and potentially misleading.

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 provided about when to use this tool or when a sibling such as validate-json, normalize-url, or wiki-title-ok would be more appropriate. The only usage-related signal, 'Query discarded,' describes a side effect, not an invocation context.

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