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

With no annotations, the description carries the full burden. It discloses that the query is discarded, which is helpful, but it doesn't mention the output format (e.g., returns a number), whether it's read-only, or why the schema contains 8 other parameters that appear unrelated. This lack of explanation could confuse an agent.

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 efficient sentence with no redundancy. It front-loads the core action. However, it is so brief that it omits necessary context, which is penalized in other dimensions; for structure alone, it's concise.

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 but only one (query) is used for the described purpose. The description doesn't explain why the others exist or how they relate. There's no output schema, and the return value is not stated. For a simple tool, this is still incomplete given the cluttered schema and lack of output information.

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 all parameters are already documented. The tool description doesn't add meaningful semantics beyond the schema—it only implies the 'query' parameter matters, but that's already clear. It adds no extra detail about parameter usage or relationships.

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), which is specific. However, it doesn't differentiate from siblings like memory-key-count or wiki-title-ok, and the phrase 'search query' is a bit vague without specifying the exact parameter. Still, it's a distinct purpose.

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 given on when to use this tool versus alternatives. The description only says what it does, not the context or criteria for selection. An agent gets no help deciding between this and other counting tools.

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