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

With no annotations, the description must carry the behavioral burden. It does disclose that the query is discarded, which suggests no persistence or side effects beyond counting. However, it does not explain how characters are counted, what the return value looks like, or any edge-case behavior, so transparency is only partial.

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, front-loaded sentences with no filler. Both sentences earn their place: one states the core function and the other discloses the discard behavior.

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 is conceptually simple, but the mismatch between the description and the input schema is a critical gap. Without annotations, an output schema, or a 'query' property, an agent cannot reliably know how to invoke this tool. The schema's wrapper note hints that more detail exists but does not provide it here.

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 documents seven string properties, but none is named 'query' and the tool description never maps 'search query' to any parameter. Schema coverage is high in a formal sense, but the property descriptions are unrelated to the stated purpose, so an agent cannot determine which value to pass. The description adds no parameter-level meaning.

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 action ('Count characters') and a clear resource ('a search query'), and it adds a side-effect note ('Query discarded'). It is specific enough to distinguish the basic operation, though it does not explicitly differentiate it from sibling counting tools or identify the actual input parameter.

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 names no sibling tools, no exclusion conditions, and no context in which this tool is preferred over related tools like memory-key-count or hn-front-count.

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