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

Annotations already flag destructiveHint=true and readOnlyHint=false, so safety is covered; the description adds real behavioral content — deterministic positions, no overlap, reserved routing gutters, separated cross-kind regions. It stops short of saying existing manual placement is overwritten and irreversible, which is the key consequence of a destructive whole-canvas rearrange.

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?

Two dense sentences, front-loaded with the core verb and scope, with the sibling comparison closing it out. Slight cost from capitalized emphasis (WHOLE, ONLY) and a long kind list, but nothing is genuinely wasted.

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 destructive, no-return-value, aggregate layout operation the description covers what changes and how the result is determined. The missing piece is the reversibility/undo story and any duration or scale caveat for a whole-canvas operation.

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 100%, and expectedProjectId is fully documented in the schema, so the baseline 3 applies; the description adds nothing about parameters. It also doesn't acknowledge that the call can be run with no parameters against the session project.

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 (Rearranges) and an explicit scope (the WHOLE canvas), and enumerates the kinds it handles (org, entity/ERD, arch, process, journey, captable). It also distinguishes itself from the nearest sibling, arrange_cells, so an agent can pick it without opening either 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 names the alternative (arrange_cells only makes a grid) and the condition selecting this tool, plus a claim of exclusivity for arch and captable. It doesn't explain when to use the per-kind siblings (auto_layout_org, auto_layout_process, auto_layout_journey) instead of this whole-canvas pass, leaving that inference to the agent.

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