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

With no annotations, the description carries the full behavioral burden. It discloses that the query is discarded, which is useful, but it does not state that only the 'query' parameter is actually used while the other eight parameters are ignored. It also omits the return format (presumably an integer count) and any edge cases. The description is too terse to fully disclose behavior.

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 waste. The core action is front-loaded and the discarded-query note is valuable. It is appropriately concise, though it could benefit from one more sentence clarifying parameter usage.

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 optional parameters and no output schema, the description is incomplete. It fails to explain that only the 'query' parameter is used and the rest are ignored, which could lead to misuse. It also does not specify the return value or any limits. Given the complexity of the parameter set, more context is needed.

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 schema already documents every parameter. The description adds minimal extra meaning: it implies only 'query' is relevant, and other parameters are ignored, but this is not explicit. Since the baseline for high coverage is 3, and the description does not significantly augment the schema, a 3 is appropriate.

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 specific verb and resource: count characters in a search query. It also adds a scoping note that the query is discarded. This is clear, though it does not explicitly differentiate from siblings like memory-key-count or hn-front-count, but those are clearly different resources. The purpose is unambiguous.

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 gives no guidance on when to use this tool versus alternatives. It does not mention exclusions, prerequisites, or any context where another tool would be more appropriate. An agent must infer from the name alone that this is for counting query length, with no explicit routing information.

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