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

No annotations are provided, so the description carries the disclosure burden. The statement 'Query discarded' usefully signals that the input is not stored or persisted, which is a genuine behavioral trait. However, the description omits the return format, error behavior, and what happens when multiple parameters are supplied, leaving important behavior undisclosed.

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. 'Count characters in a search query' is front-loaded, and 'Query discarded' is a relevant, non-redundant addition. Every word earns its place.

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?

There is no output schema and no annotations, so the description alone must explain return values and usage context. It does not state that the result is a character count integer, nor does it clarify whether only the 'query' parameter should be supplied despite the nine optional schema properties. For a tool with this much schema surface area, the description is too thin for an agent to invoke it correctly without guessing.

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 schema already documents all nine parameters, including 'query' as 'Search text; discarded after the length check.' The tool description adds no new parameter meaning beyond the word 'search query,' and it does not clarify the role of the other eight optional parameters. Baseline of 3 applies because the schema carries the semantic load.

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 action ('Count characters') and a clear resource ('a search query'), and the phrase 'Query discarded' adds a meaningful scope detail. It does not explicitly set itself apart from sibling count/shape tools like memory-key-count or hn-front-count, but the verb-resource pair is specific enough.

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 such as memory-key-count, hn-front-count, or other length/shape utilities. The description implies a simple character-count use case but gives no exclusions, prerequisites, or comparison to sibling tools.

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