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

Annotations only cover the safety profile (readOnly=false, destructive=false, openWorld=true). The description adds real behavioral context: a credit is consumed, the package must support Featured Property, an API key with app access is required, and the listing becomes publicly visible ('reaches other people'). It stops short of stating reversibility or what happens when the credit expires.

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 with the core action, which is good, but the first two sentences are near-duplicates — 'upgrade a listing to Weekly Featured Property, using one credit' is repeated almost verbatim. The confirmation and API-key notes are useful; the redundancy is not.

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 mutation tool with no output schema, the description covers the credit cost, package prerequisite, visibility implications, auth requirement, and confirmation behavior. An agent has everything needed to call it correctly and warn the user about the side effect.

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?

Only one parameter (listing_id) and schema coverage is 100%, so the schema fully documents it, including the 'from list_listings' provenance. The description adds nothing beyond that, so the baseline of 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 precise verb+resource+scope: upgrade one listing to Weekly Featured Property for a week. It is clearly distinguishable from the sibling zoopla_upgrade_to_premium by naming the exact placement type and duration.

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 preconditions — the package must include Featured Property, it consumes one credit, and confirmation is required by default. It does not explicitly contrast this with zoopla_upgrade_to_premium, so the agent must infer which upgrade tier to choose.

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