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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds non-obvious context the annotations do not: that no authentication token is required, which is a real behavioral fact affecting invocation. It stops short of describing response format or error behavior for a missing slug.

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, front-loaded sentences with no filler: the return payload first, then the input and auth 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?

With only one required parameter at full schema coverage and no output schema, the description compensates by enumerating the returned fields (URL, version, size, timestamps) and flagging the auth requirement. A reader could call it correctly; only error/not-found behavior is unaddressed.

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% for the single 'slug' parameter, so the schema already documents it fully. The description only restates 'Input: slug' without adding format, casing, or lookup semantics, so the baseline of 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 ('Returns whether a slug is live, plus its URL, version, size, and timestamps'), enumerating the returned fields so the agent knows exactly what it gets. It is clearly distinct from listing siblings (list_sites, list_versions) and analytics tools, though it never names those siblings to differentiate explicitly.

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?

'Input: slug' plus 'No token is required' gives a minimal usage cue, including a useful auth precondition. However, there is no guidance on when to prefer this tool over list_sites, get_manifest, or site_analytics, so the usage context is implied rather than stated.

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