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

Annotations already declare read-only and open-world behavior; the description adds important context beyond that: it reads from the public search page, caps results around 300, omits contact details and full post text, and explains the x402 payment and charging behavior. These details materially affect how an agent should invoke and interpret the tool.

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 a dense, front-loaded paragraph that states purpose, return shape, source, limits, omissions, and pricing without filler. Every clause carries useful information for invocation or interpretation.

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 paid read-only listing tool with an output schema, the description covers scope, ordering, result cap, omitted data, and payment behavior. An agent has enough information to call it correctly and understand the main constraints.

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%, and all four parameters are documented in the schema. The description reinforces the site/category pairing with examples and notes the result cap, but it adds little parameter syntax beyond what the schema already provides, so the baseline of 3 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?

States a specific resource and scope: current Craigslist listings for one site and category, with optional query matching. The examples and return fields make it easy to distinguish from sibling travel/car/housing tools.

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 description implies usage through category examples such as sfbay + cta and newyork + apa, but it does not explicitly say when to choose this tool over sibling alternatives or state exclusions. Usage context is clear enough to infer, but not fully guided.

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