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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds genuine value by revealing the shape of the answer (count of currently live links + open counts) and implicitly scoping to active links only, but says nothing about permissions, ownership scoping, or whether inactive/revoked links are included.

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 tight sentence with no filler, and the core information (link count, open frequency) is front-loaded. It loses a point only because the question-style phrasing is less actionable than a declarative statement of what the call returns.

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 and only a readOnly annotation, the description must explain the return payload; it sketches the key fields (live link count, open counts) but not their structure or whether per-link detail is included. Sufficient to understand the gist, not sufficient to consume the response confidently.

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 0%, so the description carries the burden of explaining planType and planId — yet it never names them. It says only 'for a plan,' leaving the agent to infer that planType (WORKOUT/DIET) and planId identify the target, and offering no format hints for planId.

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 sentence conveys the substance (a count of live share links plus open frequency for a plan), but it's phrased as a question with no verb or resource name, so an agent must infer this is a read/stats lookup. It does not distinguish itself from nearby siblings such as create_plan_share_link or revoke_plan_share_links beyond the fact that it reports rather than mutates.

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 when-to-use guidance, no prerequisites, no mention of alternatives. The agent is left to guess whether this is the right call versus create_plan_share_link, revoke_plan_share_links, or list_plan_purchases when it wants share-related information.

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