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

With no annotations, the description carries the full burden of behavioral disclosure. It discloses that the query is not retained, which is useful, but it does not explain what is returned (e.g., a number), how multiple parameters are handled, or whether any input is normalized or validated. The behavioral picture is extremely incomplete.

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 front-loaded, with both sentences contributing meaning: the operation and the non-retention side effect. It is appropriately concise, though the missing parameter mapping makes the overall structure feel incomplete.

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 tool with seven input parameters, no annotations, and no output schema, this description is far too sparse. It does not state the return format, identify the relevant parameter, or explain error behavior. An agent would need significant tool-level context beyond the description to call this correctly.

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 individually describes seven parameters, so schema coverage is high, but the description fails to connect any of them to the concept of a 'search query.' Without that mapping, an agent cannot know which string to pass for character counting, undermining the value of the parameter descriptions.

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 concrete verb and object: 'Count characters in a search query.' However, it never specifies which input parameter represents the search query, and the schema contains seven unrelated string parameters (ref, url, city, feed, host, json, path). The purpose is clear at a high level but ambiguous in terms of how to invoke the tool.

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?

There is no guidance on when to use this tool versus alternatives, no mention of prerequisites, and no indication of which schema property to populate. The only behavioral hint, 'Query discarded,' does not help an agent decide when to select this tool.

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