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

Annotations already declare destructiveHint=true, but the description goes further and explains exactly what is destroyed: "everyone who opens the short link is sent to the new URL from now on and the old destination is overwritten." This is precisely the added context annotations cannot convey.

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?

Three short, front-loaded fragments lead with WRITE and DESTRUCTIVE flags, then the concrete consequence, then the constraint and endpoint. Zero wasted words.

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 mutation tool with no output schema, the description covers the write semantics, the destructive effect, the URL constraint, and the underlying endpoint. Only the lack of sibling differentiation keeps it from being fully 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 alias, url, and domain are already documented in the schema. The description restates the http(s) constraint on url but adds nothing about alias or domain selection, 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: "point an existing short link at a new destination." The scope is narrower than a generic update, but the description never contrasts itself with the sibling tinyurl_update_link, which is the main risk of mis-selection.

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 (an existing link must be repointed) and states a prerequisite that the new URL be http(s). However, it gives no when-not guidance and does not route the agent away from tinyurl_update_link or tinyurl_create_link.

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