layout

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

Annotations only declare readOnlyHint and openWorldHint=false; the description adds real behavior beyond that: order of returns ('one box per item in input order'), edge-case handling ('notes for off-canvas or over-wide inputs'), and the no-credentials/no-network guarantee. It stops short of describing error conditions or units explicitly, so not 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?

Front-loaded with purpose, then modes, then margin constraints, then return shape and the pure-computation guarantee. Five dense sentences with no filler, though the mode list partially restates the schema's enum descriptions, keeping it just under a 5.

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 16 params, one required, no output schema, and only readOnly annotations, the description carries the return-format burden and does so ('one box per item in input order, plus notes'). It covers defaults context and edge cases; units are only implied by '(px)' comments in the schema, which is a minor remaining 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 coverage is 100%, so the baseline is 3 and the schema already documents all 16 params including defaults. The description still adds a derived fact not in the schema: the effective content column (80–880 desktop, 20–400 mobile) produced by the margin defaults, plus mode-specific mobile stacking behavior that guides which params matter.

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: 'Computes on-canvas coordinates (top/left/width/height) for a group of elements on both breakpoints.' The final clause ('Pure computation: no credentials, no network.') cleanly separates it from every sibling CRUD/render tool. An agent knows exactly what this returns without opening the 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?

The description explains what each mode does and that it respects page margins, which implies the intended scenario (getting positions before placing elements). However it never states when to reach for this tool in a workflow (e.g. before add_section/new_element) and names no alternative or exclusion. Usage is inferable but not prescribed.

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