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

With no annotations, the description must carry behavioral disclosure. It only states 'Query discarded,' implying no persistence, but it does not describe the return value, read-only nature, or how the other 8 parameters are handled. This is minimal and insufficient for a tool with multiple inputs.

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 concise but under-specified. It front-loads the action but the second sentence about discarding is vague. It is not appropriately sized because it omits essential context, so a 3 reflects the balance between brevity and missing information.

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 9 parameters and no output schema, the description is drastically incomplete. It does not explain the return value, the role of the other parameters, or when to use it. An agent cannot confidently invoke this tool correctly based on this description alone.

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 description coverage is 100%, so the baseline is 3. The description adds no extra meaning beyond the schema, only indirectly referencing the 'query' parameter. It does not clarify that only the query length is returned or that other parameters are ignored.

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 clearly states the action 'Count characters in a search query', identifying the verb and resource. However, it does not differentiate from sibling tools like 'memory-key-count' that may also count characters, so it is clear but lacks distinguishing context.

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 on when to use this tool versus alternatives. The description does not mention any exclusions, alternatives, or conditions for selection, leaving the agent without direction.

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