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

With no annotations present, the description carries the burden of disclosing side effects. It does state that the query is discarded, which is a useful transparency note, but it does not mention other behavioral aspects like return value, handling of empty input, or whether other parameters are ignored.

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 extremely concise, with no filler or redundant wording. The primary action is front-loaded and the additional note about query disposal is placed second.

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 the simple stated purpose, the schema exposes 9 optional parameters with no clarification that only 'query' is relevant. The description also omits the output format and behavior when no query is provided, leaving an agent with insufficient context for reliable invocation.

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 input schema already provides descriptions for all 9 parameters, so the baseline is 3. The tool description adds no additional parameter-level semantics beyond what the schema already states.

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 the action ('Count characters') and the resource ('a search query'), making the tool's purpose immediately understandable. It also distinguishes itself from sibling tools, none of which count query length.

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 such as normalize-url, validate-json, or other shape-checking tools. It does not mention any exclusions or preferred conditions.

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