Resize an image or embed

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

The annotations (readOnlyHint=false, idempotentHint=false, destructiveHint=false) already tell the agent this is a non-destructive mutation, and the description adds real behavior the annotations can't: the editor may accept a different width than requested and the height is always recomputed to preserve aspect ratio ('Never stretches'). It does not address permissions, side effects on surrounding layout, or what happens on failure, keeping it below a 5.

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 sentences, front-loaded with the action and the drag-handle mechanism, then the per-type parameter advice, then the non-obvious clamping caveat. Dense and largely waste-free, though the parenthetical pixel values repeat what the schema already conveys as bounds.

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 mutating UI-driving tool with no output schema, the description covers the essentials: how the resize is performed, which parameters apply per block type, and that the applied size may differ from the request. Minor gaps remain – whether the tool errors or no-ops on a non-resizable section, and whether any confirmation/result is returned – but nothing an agent needs to invoke it correctly is missing.

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 50% – `aspect` and `height` have no schema descriptions at all – and the description compensates by explaining that `aspect` is width/height (e.g. 1.7778) and that `height` is an alternative for embeds. It also gives practical magnitudes for `width` (content column ~898 px) and notes the actual accepted width may differ, adding meaning beyond the min/max constraints.

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 ('Resize the image/embed section `index` by dragging its corner handle') and names the sibling tools that create the block (gsites_add_image) and enumerate the index (gsites_list_sections). An agent can distinguish this from gsites_add_image, gsites_add_embed, or gsites_move_section without opening any schema.

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?

It routes usage by block type: images take width (height follows proportions), while embeds/videos take `aspect` or `height`. It also gives the motivating context (images from gsites_add_image arrive at ~283 px). It stops short of saying what to do if the indexed section is not an image/embed or whether to call gsites_list_sections first, so it is clear but not fully exclusionary.

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