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

With no annotations, the description carries the full behavioral burden. 'Count characters' and 'Query discarded' communicate that this is a stateless, non-persistent operation, which is useful. However, it does not disclose whether the other eight schema parameters are ignored, whether query is required, or what happens when called without the query field.

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 sentences with no filler. The verb and object are front-loaded, and 'Query discarded' adds behavioral information without repeating the tool name.

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 nine optional parameters, no annotations, and no output schema, but the description only addresses the query input. It does not explain whether the other parameters are ignored, whether query is actually required, or what the tool returns. This leaves too much call-shape ambiguity for an agent.

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 the baseline is 3. The description adds little beyond mapping 'search query' to the query parameter; the per-parameter semantics are already fully documented in the schema. It does not clarify the role of the many unrelated-looking parameters.

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 specific action and resource: 'Count characters in a search query.' This is reasonably distinct from sibling count tools and aligns with the tool name. It is not a 5 because it never names the exact parameter that holds the search query and does not specify the form of the return value.

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 about when to use this tool versus alternatives, no exclusions, and no clarification of which of the nine optional parameters should be supplied. The description does not help an agent decide how to invoke this tool correctly.

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