Validate Pinterest URL

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the description does not need to repeat those. It adds useful behavioral context by stating 'without making a network request,' which is not captured in the annotations. This conveys a key runtime behavior that helps the agent understand the tool's cost and side-effect profile.

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 a single, compact sentence that front-loads the primary behavior ('Return whether') and adds a key qualifier ('supported Pinterest URL') and a constraint ('without making a network request'). Every word earns its place; no wasted or redundant phrasing.

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 boolean validator with one parameter, the description is complete. It explains the core behavior, and the annotations cover safety and idempotency. An output schema exists, so return-value details are not needed. The tool's simplicity means no additional context is necessary for correct invocation.

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?

The schema has 100% description coverage for the 'url' parameter ('A complete Pinterest or pin.it URL'), so the baseline is 3. The description adds no further parameter semantics, but since the schema fully documents the single parameter, this is sufficient. No gap exists that the description must fill.

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 tool's function: 'Return whether a value is a supported Pinterest URL.' This is a specific verb+resource combination that distinguishes it from sibling tools like parse_pinterest_url and normalize_pinterest_url, which perform different operations.

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 context for when to use this tool: 'without making a network request' suggests it is a lightweight, local validation. While it does not explicitly name alternatives, this context differentiates it from parsing or normalizing, which are distinct operations. No exclusions are mentioned, but the usage scope is clear.

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