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

Goes well beyond the annotations: it discloses that the record is Private by default and reaches no one, that it runs without a confirmation prompt and why (nothing goes public and set_listing_status can delete it), and that a Cotlet API key with access to this app is required. This is real safety, side-effect, and auth context the annotations do not carry.

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 core facts are front-loaded, but the Private/not-on-Zoopla point is stated three times across the opening sentences ('saved as Private so it is not on Zoopla', 'saves it as Private, so it is not on Zoopla and reaches no one'). Trimming the restatement would sharpen an otherwise tight description.

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 essentials an agent needs: default private state, auth requirement, the publish path via a named sibling, and the duplication option. It does not describe the return value (e.g. the new listing ID), which would have closed the last gap.

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 schema already documents all seven parameters, setting the baseline at 3. The description adds genuine meaning only for copy_from_listing_id via the 'Create similar in ZooplaPro' analogy; price, address, details, and department are left entirely to the schema.

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 and resource ('Creates a listing') and immediately establishes scope: saved as Private, manual uploaders only. It distinguishes itself from the sibling set_listing_status by naming it as the publish step and from update_listing by framing this as the creation path.

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?

Explicitly routes the agent: publish with set_listing_status, start from an existing or deleted listing with copy_from_listing_id, and manual uploaders only. It names the alternative tool and the condition (publishing) that selects it, so an agent can decide between creation and status changes without guessing.

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