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

Annotations already declare destructiveHint=true and readOnlyHint=false, but the description does not say what is actually destroyed or replaced — whether an existing piece of the same name is overwritten, whether new pieces are created, or what the call returns. 'Write one piece whole' hints at full replacement but stops short of stating the consequence.

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?

A single front-loaded sentence with no padding; the parenthetical carries real content (required html structure) rather than restating the name. Slightly cryptic phrasing ('write one piece whole') costs a little readability.

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?

This is a destructive 5-parameter write with no output schema and only 40% schema coverage, so the description needs to do more. It omits overwrite semantics, the relationship to ads_edit_piece, and any indication of what happens to an existing piece with the same name.

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 only 40% (name and document_id are described; html, width and height are bare). The description partially compensates by giving the unit for the size fields ('in px') and by specifying that html must contain style blocks and a lamina section — useful meaning the schema does not carry. It still says nothing about the expected html for the two required dimension integers beyond units.

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?

Specific verb+resource: 'Write one piece whole', and it names what the piece consists of ('<style> blocks and its <section class="lamina">') plus the size in px. It does not differentiate itself from the sibling ads_edit_piece, so an agent must infer that this creates/writes a full piece rather than patching one.

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?

No when-to-use, when-not-to-use, or alternative named. With ads_edit_piece, ads_read_piece and ads_list_pieces as siblings, the description never says to use this for a brand-new or full replacement instead of a targeted edit.

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