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

No annotations are provided, so the description carries the burden. It states the tool returns counts across the live index, which implies a read-only aggregation operation. However, it doesn't disclose details like whether counts are approximate, how the live index is defined, or whether there are limits on the counts returned. The description is honest but minimal.

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 one sentence with no wasted words. It front-loads the core function (counts by dimensions) and then gives the usage directive. Every word earns its place.

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 zero-parameter aggregation tool, the description is nearly complete. It explains what the tool does and when to use it. The only missing context is what the output looks like (e.g., a map of dimension to counts) and whether there are any caveats about the live index, but the absence of an output schema and parameters lowers the burden. A 4 is fair.

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 tool has zero parameters, so the schema is trivially complete. The description adds meaning by explaining what the counts are grouped by (source, category, country, tag), which is the entire semantic payload. With no parameters, a baseline of 4 is appropriate, and the description fully compensates.

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 tool counts jobs by source, category, country, and tag across the live index. It also distinguishes its purpose from siblings by saying to call it first to learn what filters are useful, which differentiates it from get_job and search_jobs.

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?

The description explicitly says when to use this tool: call it first to learn what filters are useful. This implies it should be used before search_jobs to inform filter choices, and it is not for retrieving individual jobs or search results. It provides clear context and a usage directive.

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