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

Annotations already convey that this is a mutating operation (readOnlyHint false) and not idempotent or destructive. The description adds the useful behavioral fact that it returns a shortUrl suitable for sharing, which partially compensates for the lack of an output schema. It does not discuss uniqueness constraints on alias, plan restrictions on expiration, or error behavior, but this is not required at a high level.

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?

Two sentences with no filler. The core purpose is front-loaded and the return value is stated immediately after, which is exactly what an agent needs to know first.

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?

The tool has a clear creation purpose, all five parameters are fully documented, annotations cover the mutation profile, and the description names the primary output (shortUrl). With no output schema, it would be slightly stronger to mention other possible response fields, but for a link creation tool this is sufficiently 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 description coverage is 100%, so every parameter already has a detailed description. The tool description adds minimal information about the URL relationship but does not need to because the schema carries the load. Baseline 3 is appropriate for this complete schema coverage.

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: 'Create a short link that redirects to a URL.' This clearly distinguishes it from the sibling tools delete_link, get_link, list_links, and update_link by the action it performs.

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 use case is implied by the name and description, but no explicit guidance is given about when to choose this tool over siblings, such as 'use this to create a new link, update_link to modify existing, delete_link to remove.' An agent can infer it from the name, but the description does not state exclusions or alternatives.

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