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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed-world scope, so the safety profile is fully covered. The description adds only the shape of the returned metrics, and since an output schema exists that job is already done, so it contributes little behavioral context beyond the annotations.

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?

A single dense sentence with no filler, front-loaded with the purpose and followed by the metric list. Every clause 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?

With an output schema, full annotation coverage, and 100% schema description coverage, the description only needs to establish purpose and scope, which it does. The minor omission is that default scoping (falling back to the caller's own card) is handled by the schema rather than the description, which is acceptable given the surrounding coverage.

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%: both slug (defaults to the authenticated user's own card) and apiKey (only needed without an Authorization header) are fully documented in the schema. The description adds no parameter detail, so this is the baseline case where the schema does all the work.

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 ('View statistics') and resource ('business card'), then enumerates the exact metrics returned (views, saves, saves to contacts, click counts by link type, last-activity timestamps). This is clearly distinguishable from siblings like get_card or get_leads, which would return card content and lead records rather than aggregate metrics.

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 enumerated metrics imply when the tool is useful (when aggregate stats are wanted rather than raw records), but there is no explicit when/when-not statement and no mention of alternatives such as get_leads or get_card. Usage is inferable but not stated outright.

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