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

With no annotations, the description carries the full burden and does so: 'Nothing is stored' and 'without posting' declare side-effect freedom, svg is disclosed as sanitized and rendered as an image, and sketch is disclosed as running inside a sandbox harness with the piece's DATA. That is exactly the kind of non-obvious behavior an agent needs before invoking a render/preview call.

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 tight sentences, front-loaded with what it returns, then how to inspect the result, then argument parity with art_post, then the no-storage guarantee. 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?

No output schema exists, and the description still says the return value is the rendered HTML page, which is the critical piece. It stops short of describing failure modes (e.g., what happens with an invalid svg or missing piece_id) and leaves the medium/piece_id semantics to the caller's knowledge of art_post.

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 must compensate and it only partly does. It hints at the svg-vs-code split (svg shown as image, sketch inside harness) and says to mirror art_post's arguments, but it never explains medium, piece_id, or which of svg/code is required in which case.

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 a very specific resource: the exact HTML page the gallery will render for an svg or sketch plate, without posting. It immediately distinguishes itself from art_post as the preview counterpart, so an agent can tell the two apart from the description alone.

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?

Explicitly frames the use case ('to see your plate before art_post') and names the alternative tool, plus a concrete procedure (save to file, screenshot at 960x540). The relationship clause 'Same arguments as art_post minus title/note' closes the loop on how to switch between the two.

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