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

With no annotations, the description must carry the full behavioral burden. It discloses that the query is discarded, but it does not explain why the schema includes eight additional unrelated parameters (ref, url, city, feed, host, json, path, zone) or what happens to them. The description gives no hint about side effects, reversibility, or the stateless nature of the operation, leaving the agent uncertain about how to interact.

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: two short sentences with the purpose stated first. No wasted words. However, it is so terse that it omits crucial context about the unused parameters, which could be considered under-specification rather than good conciseness, but the structure is still efficient.

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 the description suggests only 'query' is relevant. It does not explain why the other parameters exist or whether they are ignored, which is a significant completeness gap. An agent cannot confidently know whether it must supply all parameters or only 'query'. The absence of an output schema is acceptable, but the description fails to provide the necessary context for correct 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?

Schema description coverage is 100%, so each parameter is already documented. The tool description adds no additional parameter meaning beyond the schema; it merely restates the core action. Baseline 3 applies because the schema fully handles parameter semantics.

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 verb ('Count') and resource ('characters in a search query'), which precisely matches the tool name and distinguishes it from siblings like 'memory-key-count' or 'hn-front-count'. No ambiguity about what the tool does.

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 provided on when to use this tool versus alternatives. There is no mention of use cases, constraints, or exclusions. The description only states the action without contextualizing it among the many sibling tools.

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