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

No annotations are present, so the description carries the full burden. It does disclose one behavioral trait ('Query discarded'), which is useful, but it does not state what the function returns, how it handles multiple or no parameters, or whether all parameters are treated the same. This is minimal transparency for a tool with no annotation support.

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?

Both sentences earn their place: one states the core function, the other adds a behavioral note. The description is front-loaded and free of fluff. It is short, but the brevity leaves gaps in context; still, as written it is efficient.

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 tool has 9 optional parameters, no output schema, and no annotations, so the description must clarify what an agent should pass and what to expect back. It fails to specify which parameter is the 'search query' and does not define the return value. An agent invoking this from scratch would likely be uncertain whether to pass `query`, `ref`, `url`, or another field.

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 coverage is 100%, so the input schema already documents all parameters, including their meanings and discard behavior. The description adds almost no parameter-level meaning beyond repeating the 'discarded' idea and directing attention to 'a search query,' which helps identify the `query` parameter but does not explain it more deeply.

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 verb and resource: 'Count characters in a search query.' It is not a tautology and matches the tool name. However, it does not differentiate this tool from siblings like memory-key-count or hn-front-count, which also sound counting-oriented, so it stops short of the top score.

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 there is no mention of what counts as a 'search query' among the nine optional parameters. The description gives no exclusions, prerequisites, or alternative routing, leaving the agent without usage context.

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