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

Annotations only say readOnlyHint=false and openWorldHint=true, so the description carries the behavioral burden. It does this thoroughly: it discloses the 24-hour expiry, free trial nature, safety-question gate, returned live subdomain and one-time claim token, and the requirement for a live external https target because content hosting is unavailable. This is rich and accurate behavioral context beyond the annotations.

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 and uses compact sentences for constraints. There is minor redundancy between 'Free for 24 hours' and 'Expires in 24 hours,' but the overall structure is clear, scannable, and free of filler.

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 9-parameter tool with an interactive safety-question flow, the description covers the lifecycle, constraints, and follow-up mechanism reasonably well. It mentions retry-relevant concepts through the schema and has an output schema available. It does not explicitly describe the multi-turn branching or name answer_trial_canary as the retry sibling, which would make it fully 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?

Schema description coverage is 100%, so the structured schema already documents all nine parameters. The prose adds only light value by restating the need for a goal and an https target. It does not clarify retry mechanics or enum semantics beyond what the schema already provides, so the baseline 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?

The description opens with a specific action and resource: 'Launch a memorable public URL for something you built.' It clearly frames try_domain as a free 24-hour trial with no signup or wallet, and contrasts it with a paid rental. An agent can easily tell this apart from siblings like rent_domain, search_domains, and check_availability.

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 provides clear usage context: use it to demo a deployment with a real address before committing to a paid rental, and notes the one-trial-per-agent constraint. It does not explicitly name sibling alternatives like check_availability or answer_trial_canary, but the retry-related parameters imply a follow-up flow. A direct sibling reference would make the guidance fully explicit.

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