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 that the query is discarded, which is a useful side-effect statement, but it does not say whether other inputs are ignored, whether the result is returned as an integer, or whether the operation is a pure local computation. Thus the behavioral picture is only partial.

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 only two terse sentences, with the core action front-loaded and no filler. Both sentences contribute, though the brevity contributes to the under-specification; still, as a standalone text it is neatly structured.

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?

With nine optional parameters, no annotations, and no output schema, a two-sentence description is insufficient. It does not say which parameter to pass, what the return value looks like, or that all other fields are irrelevant, so an agent cannot reliably invoke the tool correctly.

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 schema already documents `query` as 'Search text; discarded after the length check'. The tool description adds no param-specific meaning and does not explicitly tell the agent that `query` is the only relevant parameter among nine optional fields, though this is inferable.

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 uses a specific verb ('Count') and a clear resource ('characters in a search query'), and the follow-up 'Query discarded' adds a behavioral detail. It is clear enough to distinguish the core operation from URL/shape validation siblings, though it never names the `query` parameter explicitly, so it is not 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 about when to use this tool, when not to use it, or how it compares to siblings such as `memory-key-count`, `normalize-url`, or `domain-shape`. An agent must infer the appropriate context from the name and skeletal description.

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