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

Annotations already declare non-readOnly, destructive, idempotent, and closed-world. The description adds genuinely new context: the destination and click history survive, and generated codes are never reassigned, which tells the agent this is a reversible soft-disable despite destructiveHint. It stops short of describing auth requirements or rate limits, so a 4 rather than 5.

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 tight sentences with the core action front-loaded and the alternatives packed into the second; nothing is wasted and no filler precedes the useful information.

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 one-parameter, idempotent, reversible operation with output schema present, the description covers effect, data preservation, code-reuse policy, and sibling routing. Nothing an agent needs to invoke it correctly is missing.

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 single 'code' parameter is already fully documented in the schema (format, examples, full-URL acceptance). The description adds no additional parameter guidance, 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 specific verb and resource ('Turn off one of your short links') plus the concrete effect ('stops redirecting'), which immediately distinguishes it from delete_url and update_url. The preservation clause ('keeping its destination and clicks') further pins down exactly which operation this is.

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 names both alternatives with the condition that selects each: reactivate_url to turn it back on, delete_url to erase it for good. Combined with the stated effect (stops redirecting but keeps data), an agent has a complete when-to-use / when-to-use-something-else decision rule.

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