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

Annotations already declare destructiveHint=true, openWorldHint=true and idempotentHint=false, so the safety profile is covered. The description adds value beyond that by disclosing the redirect grace period for the old link, which is exactly the kind of consequence an agent cannot infer from structured fields. It stops short of stating auth requirements or what happens to the old slug once the redirect expires.

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 very short sentences with no filler, and the plan restriction is front-loaded before the behavioral note. Every clause carries 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?

The tool is simple (two required string params, no output schema, no nested objects), so not much is required. Still, the undefined parameter meaning and the absence of collision/validation behavior leave gaps an agent would hit on its first call.

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 0%, so the description carries the full burden for two required parameters, yet it never explains that slug is the current identifier and newSlug the replacement. It also omits the 3-63 character constraint and any character-format rules, leaving ambiguity about whether slug is a name or a URL slug.

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?

"Change a site's slug" gives a specific verb and resource, which distinguishes it from rename_version (versions) and update_site_details (metadata). A reader knows exactly what is mutated without opening the schema, though it does not explicitly name the sibling it replaces.

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 phrase "on Hobby and Team plans" supplies a real eligibility constraint that tells an agent when the call will fail. However, there is no guidance on when to prefer this over update_site_details or how it relates to rename_version, so the when-to-use framing is only implied.

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