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

Annotations already declare idempotent=true, destructive=false, readOnly=false, so the safety profile is covered; the description still adds real context beyond them by noting blocks keep their IDs and content and that nesting is a hard limitation. It stops short of mentioning permission requirements or failure modes if block_ids is incomplete, which keeps it from 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 tight sentences ordered by importance: what it does, how to call it, when to prefer it, and the constraint. No filler and the constraint is front-loaded rather than buried.

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 an output schema present and 100% parameter coverage, the description supplies exactly the missing decision-layer information: the alternative it replaces and the nested-block restriction. Nothing an agent needs in order to call it correctly is absent.

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% and the schema already describes block_ids as "All of the section's top-level block IDs, in the new order," so the description's instruction to pass the full ordered list largely restates structured data. Baseline 3 applies when the schema carries the parameter semantics.

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 ("Reorder the top-level blocks of a registration site section") plus the key modifier "in place," which distinguishes it from the remove/add and update_site_block siblings. An agent can pick this tool out of the large sibling list 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?

Explicitly names the alternative pattern (remove_site_block + add_site_block) and the condition that selects this tool instead ("when only the order changes"), and states an exclusion: nested blocks in stacks, rows, or grids cannot be moved here. This is the full when/when-not/alternative triad.

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