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 does mention that the query is discarded, which is a useful privacy/retention detail. However, it says nothing about side effects, network access, resource usage, or whether it reads any of the other eight parameters. This is minimal coverage for a tool with such a broad parameter list.

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 a single sentence with no fluff, making it very concise. However, it is under-specified for the tool's complexity, so while it is efficient in wording, it is not appropriately sized in terms of information content. Still, conciseness itself is achieved.

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?

The tool has 9 parameters, no annotations, and no output schema, yet the description only explains the tool's action on 'query'. It does not explain the role of the other parameters, what the tool returns (e.g., character count), or whether it performs any validation. This is severely incomplete for an agent to use the tool correctly, especially given the ambiguous parameter set.

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 description coverage is 100%, and each parameter already has a descriptive comment. The tool description does not add any meaning beyond the schema; it only highlights 'query'. Since the schema already documents all parameters adequately, a baseline score of 3 is appropriate, and the description adds no additional value.

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 verb and resource: 'Count characters in a search query.' This is specific enough to differentiate from siblings like 'memory-key-count' (counts memory keys) or 'hn-front-count' (counts items), though it does not explicitly name alternatives. The added 'Query discarded' gives a secondary hint about data handling.

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?

No guidance is provided on when to use this tool versus alternatives. There is no mention of conditions, prerequisites, or scenarios where this tool is preferred. The description only states what it does, leaving the agent to infer when it applies.

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