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

The annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the description does not need to cover safety. It adds nothing beyond that: it does not say what the return value is (a numeric total), how filtering scopes the count, or whether unauthenticated use is possible.

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?

It is one short sentence with the operation front-loaded and no wasted words. Being terse is efficient, though it borders on under-specification for a count tool.

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?

For a simple read-only count with a single fully documented optional parameter and annotations covering safety, this is roughly adequate. It never states that the tool returns a count rather than a list, which is the one piece of context an agent might want, especially with no output schema.

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 has 100% description coverage for the single 'query' parameter and points to oneuptime_describe_resource for field and operator syntax. The description's 'those a filter matches' merely confirms that the parameter filters the count, adding little meaning beyond the schema, so the baseline 3 applies.

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 names the resource ('BI Tools') and the operation ('Count'), which is enough to separate it from list_bi_tools, get_bi_tool, and the many count_* siblings. However, it mostly restates the name and title rather than elaborating on what is being counted or what the result represents.

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?

'all or those a filter matches' only clarifies that the query filter is optional; it never states when to use count_bi_tools rather than list_bi_tools (for example, to get only a total without fetching records). No prerequisites or exclusions are given.

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