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

Annotations already flag destructiveHint=true and idempotentHint=true, and the description goes well beyond them: it states exactly what breaks ('Links to the address stop opening the site'), that the effect is irreversible except by re-assigning the address, and it instructs the agent to confirm with the user first. This is precisely the extra 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?

Two sentences, front-loaded with the action and effect, followed by sourcing and the irreversibility warning. Every clause earns its place with no redundancy.

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?

With annotations carrying the safety profile and no output schema needed for a void-return mutation, the description supplies everything an agent needs: what the tool does, where the input comes from, that the effect is destructive and non-reversible, and that user confirmation is expected.

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 coverage is 100%, so the baseline is 3. The description adds genuine meaning by defining what qualifies as an 'old address' and pointing to get_site/set_site_slug as the sources, which the schema alone does not establish, though it adds nothing about the workspace_id parameter.

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 ('stop') and resource ('old address forwarding to a site') and immediately names the effect ('leaving the address free for any site to take'). An agent can distinguish this from siblings like rename_site, set_site_slug, and remove_custom_domain without opening any 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?

Tells the agent where the old addresses come from ('the `old_addresses` of get_site, and what set_site_slug reports after a rename'), which is the key precondition for calling it correctly. It does not explicitly name a competing tool or state when NOT to use it, so it falls short of a 5.

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