list_marketplace

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

Annotations declare readOnlyHint=true and idempotentHint=true, which the description aligns with by describing a read-only browse operation. The description adds valuable behavioral details: server-side filters, pagination limits (1000 with filters, up to 5000 without), and return fields. No contradiction.

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 well-structured with a clear opening sentence stating purpose, followed by return fields, then detailed parameter explanations. Every sentence is informative and no fluff. Front-loaded with the most critical information.

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?

Given the tool has 8 optional parameters and no output schema, the description covers purpose, parameter details, and behavioral differences. It omits explicit error handling or rate limits, but the read-only and idempotent annotations reduce the need. The return fields are mentioned, so it is mostly complete.

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?

With 100% schema coverage, baseline is 3. The description adds meaning beyond the schema by explaining the query substring semantics (including exclusion with '-'), pagination modes (with vs. without filters), and sort defaults. This adds value, hence a 4.

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 is for browsing domains for sale on the Porkbun marketplace, distinguishing it from related tools like list_domains (which likely lists owned domains) and check_domain (availability). It explicitly mentions 'aftermarket — domains owned by other users, not new registrations' and lists the returned fields.

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 for searching/sorting aftermarket domains and explains filter behavior (with filters vs. without). However, it does not explicitly state when not to use it or name alternative tools for other domain operations, though the clarity of purpose compensates.

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