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

Annotations declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so no contradiction. The description adds context beyond annotations by explaining that the numbers represent daily deliverable volumes and that they determine webhook package counts. This is valuable behavioral context that helps the agent understand what the data means and how it's used.

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 concise, one sentence with a dash to add detail. It front-loads the purpose (listing plans) and explains the key fields. Could be slightly more structured but it's efficient and to the point. No wasted words.

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 read-only tool with no output schema, the description explains what data will be returned and provides context on how it's used (decides webhook package counts). There's no missing information that an agent needs to decide whether to call this tool. The description fully covers the tool's purpose and the meaning of its output fields.

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?

There are no parameters, so the schema provides no parameter descriptions (100% coverage of an empty schema). The description explains the meaning of the fields that will be returned (price, videos_per_day, etc.), which is essential because the agent can't know what the output contains otherwise. This fully compensates for the lack of a schema description.

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 it lists subscription plans with price and daily deliverable volumes (videos_per_day, carousels_per_day, posts_per_day). It tells the agent these numbers determine how many packages a webhook will receive, which is useful. However, it doesn't explicitly distinguish itself from other list tools (e.g., package_list, brand_list) by noting it's about plans, though the name and content imply that.

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?

It doesn't explicitly state when to use this vs alternatives. It mentions the data is relevant to webhook package counts, but doesn't say 'use this when you need plan pricing/limits' or contrast with package_list. The context is implied by the content but no exclusions are given. Could be improved by noting that this gives the plan-level quotas, not actual usage.

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