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

Annotations already provide readOnlyHint=true and openWorldHint=true, indicating a safe, non-destructive read. The description adds specificity about what is read (status, URL, original expiry), which is valuable context beyond the annotations. It does not contradict the annotations and adds useful detail about the operation's scope.

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?

A single, well-structured sentence that front-loads the verb 'Read' and immediately states the target and the fields. There is zero filler, and every word adds value. It is appropriately sized for the simplicity of the operation.

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 simple read operation with one parameter and no output schema, the description covers the essential semantics: what is read and from what. It doesn't mention error cases (e.g., non-existent preview) or the exact response format, but for a read-only tool with annotations indicating safety, this is largely sufficient. The openWorldHint suggests the world may change, but that's annotation-provided. The description is adequate for an agent to know what to expect.

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 0%, so the description must compensate for the parameter. The only parameter is preview_id, with a pattern suggesting an ID format, but the description does not explicitly state that preview_id is the identifier of the preview to read. The phrase 'existing preview' hints at it, but no explicit mapping is given. This is minimal compensation for a low-coverage 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?

The description clearly states the action ('Read') and the resource ('existing preview'), and specifies the exact data returned (public status, URL, original expiry). It is immediately distinct from sibling tools like create_preview, delete_preview, and update_preview, which are mutations, and from get_deploy_instructions/get_operation_status, which target different resources.

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 context: it is for reading preview metadata, not for creating, updating, or deleting. While it doesn't explicitly name alternatives or exclusion conditions, the purpose is clear enough that an agent would not confuse it with the mutation tools. However, it doesn't mention when to prefer this over get_operation_status, which could also relate to preview state.

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