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

No annotations are present, so the description carries the transparency burden. It does disclose that the query is discarded, which is useful. But it does not state the return format, what happens if `query` is omitted, or how the other optional parameters are treated, leaving important behavioral gaps.

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 two short sentences with no filler. The purpose is front-loaded, and the side-effect statement 'Query discarded' earns its place. This is an appropriately concise structure for a simple counting tool.

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?

Despite 100% schema description coverage, the tool has nine optional parameters, no output schema, and no annotations. The description is not complete enough for an agent to confidently invoke it: it fails to specify that `query` is the only relevant parameter, what the return value looks like, or what happens when multiple parameters are supplied.

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 tool description adds no parameter-specific semantics, though the `query` parameter's schema description ('Search text; discarded after the length check') aligns with the tool's stated purpose. The unrelated parameters remain confusing because the description does not clarify their role.

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 specific verb and resource: count characters in a search query. The name 'search-query-len' reinforces this. It is distinguishable from sibling counting tools like memory-key-count or hn-front-count, but it does not explicitly tie the purpose to the `query` parameter or address the many unrelated schema fields, 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?

The description implies the tool should be used when an agent needs the character count of a search query. However, it provides no explicit guidance about when not to use it, no alternative tool mentions, and no clarification that the other eight schema parameters are irrelevant or ignored.

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