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

No annotations exist, so the description carries the full burden. It discloses that the query is 'discarded,' which is useful, but it does not explain the return value, whether other schema fields are ignored, or any side effects. The 8 extra parameters in the schema further obscure actual 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: the core purpose appears in the first sentence, and the second sentence adds a useful behavioral note about discarding the query. No words are wasted, though more content is needed elsewhere.

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 9 optional parameters, no annotations, and no output schema, this definition is incomplete. It does not state which parameter is the search query, what the tool returns, or how extra parameters are treated. An agent would likely need external knowledge to call this tool reliably.

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 structured schema already documents each parameter. The description adds only the character-count intent and does not clarify how the 9 optional fields relate to the tool's purpose, but it does not need to compensate for missing schema 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 clear verb and resource: 'Count characters in a search query.' This makes the core intent unambiguous and distinct from counting-oriented siblings like memory-key-count or hn-front-count. However, the input schema lists 8 additional unrelated optional parameters, which muddies the apparent scope slightly.

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, and no mention is made of which parameter(s) should be provided. The schema marks no parameters as required, so an agent cannot tell whether to pass only 'query' or whether the other fields are relevant. This is effectively no usage guidance.

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