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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions 'Query discarded', which is a mild transparency about the query parameter, but it fails to disclose that all other parameters are also discarded after their respective checks. The description does not cover side effects, security, or what happens with the inputs beyond counting, leaving significant behavioral ambiguity.

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 concise at two sentences and front-loads the primary purpose. However, it is under-specified for a tool with nine parameters and no annotations. The brevity results in a lack of essential context, making it more under-specification than genuine conciseness. It is efficient but not adequately informative.

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 nine parameters, no annotations, and no output schema, this description is critically incomplete. It does not explain what the tool does with the other eight parameters, what the return value is (presumably an integer length), or any behavioral constraints. An agent cannot reliably determine the tool's full behavior or expected input handling from this description alone.

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?

The schema provides 100% description coverage for all nine parameters, so the baseline is 3. The description adds minimal value: it only reaffirms that the 'query' parameter is used for length counting, which is already stated in the schema ('discarded after the length check'). It does not clarify the role of other parameters beyond what the schema already says, so it neither enhances nor detracts from the schema's clarity.

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 action: counting characters in a search query, which maps to the 'query' parameter. However, it does not clarify that the tool also accepts eight other parameters that are all discarded, nor does it differentiate itself from sibling tools like memory-key-count or hn-front-count. The purpose is partially clear but lacks scope precision.

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?

The description offers no guidance on when to use this tool versus alternatives. It does not mention any exclusions, prerequisites, or specific scenarios. An agent has no information to decide between this and similar counting tools, making the usage guidance entirely absent.

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