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

With no annotations, the description carries the full behavioral burden. It does disclose that the query is 'discarded,' which is useful, but it does not mention what is returned, whether there are side effects, or how the tool behaves with the other eight parameters in the schema.

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 only two short sentences, front-loads the primary action, and contains no filler. Every phrase earns its place, and the key behavioral note about discarding the query is included.

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 no output schema, no annotations, and nine optional parameters, the description is too sparse. It does not explain the return value, the purpose of the other schema properties, or why they are present. An agent could easily call it with the wrong parameter or expect a different result.

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 little beyond the schema, repeating the 'discarded' behavior for the query parameter. It does not clarify why nine parameters exist or which one represents 'a search query,' though the schema's `query` description is clear.

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 resource: 'Count characters in a search query.' This is specific enough to distinguish it from sibling shape/validation tools like wiki-title-ok or domain-shape. It could be slightly stronger by explicitly naming the `query` parameter and the numeric return value.

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 about when to use this tool versus alternatives such as memory-key-count or think-steps. The description only states what it does, leaving the agent to infer the appropriate use case without any contextual or exclusionary signals.

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