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

With no annotations, the description carries the behavioral burden, but its only explicit behavioral note, 'Query discarded,' is already present in the schema's query parameter description. It does not disclose behavior with multiple parameters, empty input, or the return format, and it adds little beyond the schema's existing 'discarded after the length check' note.

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 two short sentences with no filler. The action is front-loaded, and the discard note is a separate concise sentence.

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?

The description is minimally viable: an agent can likely infer to pass `query` and receive a character count. However, with 9 optional parameters, no required parameters, no annotations, and no output schema, the definition should explicitly state that `query` is the intended input, that other fields are not relevant, and what the returned value looks like.

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 parameter-level guidance: it never identifies `query` as the relevant field or explains why the other eight optional fields exist. The schema descriptions are individually clear but collectively confusing.

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 a specific operation ('count characters') and a specific resource ('a search query'), and it is not a tautology. It is distinguishable from sibling count tools like memory-key-count and hn-front-count by the search-query resource. However, it does not map this purpose to the nine-parameter schema, leaving some ambiguity about what exactly should be supplied.

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 about when to use this tool versus alternatives, no exclusions, and no mention of related tools. The only usage signal is the implied purpose from the description, which is thin given the large sibling list containing several similar count/shape-check tools.

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