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

Annotations already cover the safety profile (not read-only, open-world, non-destructive), so the bar is lower. The description adds meaningful context beyond that: it consumes credits, returns the expiry date and remaining credits, requires a Cotlet API key, and confirms each call by default. No contradiction with 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?

Front-loaded and readable, but it repeats itself: 'Uses credits' and 'pays with credits' say the same thing, and the upgrade mechanics are restated across two sentences. Some trimming would improve it.

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 3-parameter mutation with no output schema, the description covers the important angles: cost (credits), return values (expiry, credits left), exclusions (Spotlight), and auth/confirmation requirements. Minor gaps like credit-balance prerequisites remain, but it is largely 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 coverage is 100%, so the schema already documents all three parameters. The description restates the duration (15 days or 1 month) and level (featured/premium) options but adds no syntax or format detail beyond the schema, so baseline 3 applies.

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 verb (upgrade) and resource (live listing) and names the exact operations (Featured/Premium). It even excludes a related concept (Spotlight). However, it doesn't contrast with sibling tools like publish_listing or update_listing, so sibling differentiation is weak.

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?

Gives clear context: applies to a live listing, uses credits, and explicitly excludes Spotlight. It also notes the confirmation and API-key prerequisites. It stops short of naming alternative tools for related tasks, so it isn't a full when/when-not/alternatives statement.

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