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

Annotations already declare destructiveHint=true, idempotentHint=true, and openWorldHint=true; the description adds genuinely new facts: the operation is atomic ('a missing or repeated id rejects the call and nothing moves'), it takes effect on the live page immediately, and it returns the resulting page. It does not clarify interactions with hidden/unpublished blocks or what happens to blocks added concurrently, so it stops short of a 5.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?

The operational content is dense and well ordered: constraint, side effect, alternative. The opening two sentences about the business's own store and Stripe payment flow are scene-setting that does not help an agent decide or invoke, costing it a perfect score.

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 3-parameter mutation with no output schema, the description covers prerequisites, atomicity, live-effect warning, and the return shape. Missing only edge-case behavior (e.g., interaction with hidden blocks or the published/unpublished state), which an agent might reasonably need.

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, but the description reinforces the critical invariant on blockIds (complete, no duplicates, ordered) as a hard rejection condition rather than just a formatting note. workspaceId and idempotencyKey are only covered by the schema, which limits it to a 4.

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 blocks of the public store page') and even names the return ('return the page as it now looks'). It is clearly separable from near-siblings like update_store_block, add_store_block, and hide_store_block.

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?

Gives the prerequisite (get ids with list_store_blocks), the exact validity contract (every id once, top to bottom), and an explicit alternative for a different intent ('To take one block off the page without deleting it, use hide_store_block'). It also instructs confirming with the user because the live page changes at once.

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