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

With no annotations, the description carries the full behavioral burden, but the only behavioral statement ('Query discarded') largely repeats the query parameter's schema description. It does not disclose that the other eight parameters are likely ignored, whether the query parameter is required, or what the return value looks like.

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. Every word contributes to the core message: count the query's characters and discard the query.

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 string parameters and no output schema, a one-line description is insufficient. It does not state whether the character count is the only output, what happens when no query is provided, or why the other parameters are accepted, leaving an agent to guess how to invoke it 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 coverage is 100%, so the baseline is 3 because the schema already documents all parameters. The description adds minor clarification that the count is in characters, but it does not explain which parameter is the search query or how the unrelated parameters should be handled.

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 object: 'Count characters in a search query.' It clearly identifies the core function and avoids tautology. It does not explicitly differentiate from sibling length-related tools like memory-key-count, so it falls 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?

There is no guidance about when to use this tool versus alternatives, no preconditions, and no exclusions. The description only says what the tool does, not when an agent should select it.

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