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

With no annotations, the description must disclose behavior. It states 'Query discarded' but does not clarify that other parameters are ignored, nor does it mention the return value (presumably a count). It lacks a safety profile (read-only, no side effects) and does not explain what happens with the other 8 parameters.

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 a single sentence, which is concise, but it omits essential details like the return type and the fact that only the 'query' parameter is used. It is under-specified rather than efficiently concise; it could be improved with one more sentence clarifying scope.

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 tool with 9 parameters and no output schema, the description is incomplete. It does not clarify that all parameters except 'query' are irrelevant, nor does it explain the expected output (a character count). An agent cannot confidently invoke this tool without additional 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 each parameter is already documented. The description adds no extra meaning about which parameter is the 'query' or that only 'query' matters. It does not compensate for the potential ambiguity introduced by having 9 optional parameters.

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 ('count') and resource ('characters in a search query'), and the tool name reinforces the intent. However, it does not explicitly name the 'query' parameter as the input, leaving slight ambiguity given the schema has 9 parameters. It distinguishes from most siblings by its specific focus on search-query length.

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 alternatives like 'memory-key-count' or 'hn-front-count'. No explicit context or exclusions are provided; the agent must infer usage solely from the name and description.

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