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

Annotations already declare destructiveHint=true, idempotentHint=true and readOnlyHint=false, so the safety profile is covered. The description adds genuinely new context — the Pro plan gate and the ~1 minute propagation delay — but does not say the previous destination is permanently replaced or whether the change is reversible, which matters for a destructive op.

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 short sentences, zero filler, with the plan restriction and the core action front-loaded before the propagation note.

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?

An output schema exists, so return values need no explanation, and with only two fully documented params the surface is small. What's missing is the destructive consequence — that the old destination is lost — which an agent might want to confirm before calling.

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% and the schema docs both params well, including the short-code format example. The description adds nothing about parameter formats or constraints beyond what the schema already provides, so the baseline 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: point an existing short link at a new destination URL. This is clearly distinct from shortening a new link (shorten_url) or toggling state (deactivate_url/reactivate_url), so an agent can route without opening a schema.

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 'Pro only' qualifier gives a real precondition, and 'existing short link' implies the tool is for links that already exist rather than new ones. However, no alternatives are named and there is no explicit statement of when not to use it versus shorten_url or update_app_link.

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