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

No annotations are provided, so the description carries the behavioral burden. It does disclose one meaningful behavior: 'Query discarded' indicates the input is not retained. However, it does not state that other parameters are ignored, what the return value looks like, or whether any side effects occur beyond counting.

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?

Two short sentences with the core action front-loaded. 'Query discarded' is a compact, non-redundant behavioral detail. There is no filler or repetition.

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 simple length-check tool, the description is nearly adequate, but it leaves key invocation details implicit: with 9 optional parameters and none required, it never says to pass the `query` parameter, nor does it explicitly state that the result is an integer character count. The schema partially compensates, but the description alone is not fully complete.

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 meaning beyond the schema; the query property already identifies 'Search text; discarded after the length check.' No additional semantic value is provided.

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 specific action ('Count characters') and a clear resource ('a search query'), matching the tool name. It does not explicitly distinguish from sibling counting tools like memory-key-count or hn-front-count, so it stops short of a 5.

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 on when to use this tool versus alternative tools, no exclusions, and no mention of which sibling tools it complements or replaces. The intended use is implied by the name and the query parameter, but never stated explicitly.

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