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

With no annotations, the description carries the burden of explaining behavior. It discloses the effect of omitting `place_slug` (falls back to directory plans) and lists the return fields (name, description, price, billing cycle, perks, checkout URL). While it doesn't explicitly state read-only semantics, 'List' implies that, and the output details are useful. It could have mentioned permissions or potential empty results, but it is above average.

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 front-loaded with the core purpose in the first sentence. It uses three sentences, each earning its place: purpose, parameter behavior, and return data. No filler or redundancy.

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 tool with one optional parameter and no output schema, the description fully covers what the tool does, how to use it, what happens with different inputs, and what results are returned. The return field list compensates for the missing output schema. It is complete for the agent to select and invoke correctly.

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 schema already provides a highly descriptive explanation of `place_slug`, including that it comes from `search_places` and the behavioral difference when omitted. The description adds a usage recommendation ('what you want in almost every case') and examples like 'monthly/annual membership', but these are guidance-oriented rather than new parameter semantics. Since schema coverage is 100% and baseline is 3, this is appropriate.

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's function: 'List membership or subscription plans (Wix Pricing Plans).' It uses a specific verb and resource, and distinguishes itself from sibling tools by focusing on pricing plans rather than products, events, or bookings. The addition of 'Wix Pricing Plans' gives domain context.

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?

Explicit guidance is provided: pass `place_slug` to get a venue's plans, and omit it to get the directory's own plans, with the note that 'that is what you want in almost every case' and that most sites don't have directory plans. This clearly tells the agent when and how to use the tool, including the recommended input.

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