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 genuine context beyond them: what the agent/user actually receives (page or per-block captures, desktop and mobile, edit link, and a live link only when the page is published) and that a site preview shows its home page. Return-shape detail is described informally rather than exhaustively, but that is adequate for a read-only tool.

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?

The core action and the blockId scoping are front-loaded, and the trailing sentence carries the trigger condition. The middle clause stacks several parentheticals (block types, sibling tool names, link types), making it dense, but no sentence is padding.

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 4-parameter read-only preview tool with no output schema, the description covers what is produced, the draft/published distinction, per-block capture and the calling context. Only the pageId parameter and the tablet device option remain undocumented anywhere, a small residual gap.

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 only 25%, so the description must compensate. It does explain blockId's scoping effect and implies the draft/published choice via 'si la page est publiée', but it never clarifies pageId's role or that devices also accepts 'tablet' (it only mentions ordinateur et mobile), leaving a gap against the enum.

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?

The description states a concrete verb and resource: show the user screenshots of a page (or a single block) for desktop/mobile, plus edit and live links. That is far more specific than the title 'Show preview'. It does not, however, distinguish itself from the similarly named sibling capture_page_images, so an agent could still hesitate between the two.

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?

Explicit timing is given: call it after a creation, a series of modifications, or a publication, and it points to list_forms / get_page_structure when a blockId is needed. There is no when-not guidance or named alternative (e.g., capture_page_images), which keeps it below a 5.

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