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

The phrase 'Query discarded' provides useful behavioral information about data handling, which is valuable since no annotations are present. However, the description does not disclose other behavioral traits such as whether any network call occurs, what the output format is, or why the other eight parameters exist and are also discarded. It partially carries the transparency burden but leaves gaps.

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, consisting of two short sentences with no filler. The main action is front-loaded, and the second sentence adds a relevant behavioral note. It earns a high score for efficiency, though it could be slightly more informative without losing conciseness.

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?

With nine parameters, no output schema, and no annotations, the description is insufficiently complete. It does not explain the role of the other eight parameters, which parameter to treat as the search query, or what the tool returns besides a character count. An agent would likely need additional inference to use the tool 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 description coverage is 100%, so each parameter already has a clear description. The tool description adds no parameter-level meaning, but the schema fully compensates. Baseline of 3 is appropriate because the schema carries the heavy lifting.

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 verb ('Count characters') and the resource ('a search query'), making the core purpose easy to grasp. It does not explicitly contrast with sibling tools, but the operation is distinct enough from the validation/fetch tools in the list. Minor ambiguity remains about which parameter constitutes the 'search query'.

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 on when to use this tool versus alternatives. The description gives no context about scenarios, prerequisites, or when another tool might be more appropriate. The agent must infer usage from the tool name alone.

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