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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), and the description adds real behavioral value beyond them: 'Always a live count' discloses that results are uncached/real-time rather than a stored rollup, and it pre-announces that the response reports the effective date range and read timestamp. It does not mention permission requirements, but with full annotation coverage that is a minor gap.

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?

Three short sentences, front-loaded with what is counted and how it is broken down, followed by the behavioral note and the date rule. Every sentence carries information an agent needs; nothing is redundant with the title.

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 no output schema, the description usefully compensates by naming the breakdown dimensions and the response's range/read-time metadata. It stops short of explaining the shape of the breakdown (e.g., whether dimensions are cross-tabulated or separate), which is the one thing an agent might still guess at.

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 id, start_date and end_date are already documented with format and the all-time rule. The description reinforces the 'both dates or neither' semantics but adds no syntax or edge-case detail beyond the schema; 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?

States a specific verb and resource: click counts on a teammate's signature links, with the exact breakdown dimensions (country, browser, OS, device). That distinguishes it in practice from get_teammate_signature and list_signature_links, though it never names those siblings explicitly.

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?

Gives clear guidance on the date parameters ('Leave out both dates to count all clicks ever'), which is genuine usage instruction. However, it offers no guidance on when to choose this tool over get_teammate_signature or list_signature_links, and no preconditions are stated.

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