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

Beyond the annotations, the description discloses the most important behavioral fact: calling it mutates nothing, it returns a preview plus a confirmation link, and only the merchant on that page can complete the change. That is high-value context not derivable from readOnlyHint=false/destructiveHint=false. There is mild tension between 'Calling this changes nothing' and readOnlyHint=false, but the description explains rather than contradicts the conservative annotation (the tool is part of a write flow).

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 flow description is front-loaded and earns its place, but the 'Money is integer minor units (cents)' sentence is dead weight for a tool with a single non-monetary enum parameter and dilutes an otherwise tight definition.

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 no output schema, the description correctly covers the return shape (a change preview and a confirmation link), which is what an agent needs to sequence this two-step flow. Only the irrelevant money sentence detracts from an otherwise complete picture.

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 the accountsMode enum values are thoroughly documented in the schema itself. The description adds no parameter-level detail — the one sentence about money is irrelevant to accountsMode — so baseline 3 is correct.

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?

The opening sentence states a specific verb and resource ('Choose whether shoppers can sign in') and is distinguishable from the neighboring settings_* tools. The stray sentence 'Money is integer minor units (cents)' is unrelated to any parameter of this tool and slightly muddies an otherwise crisp purpose statement.

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?

Usage is implied rather than stated: the description explains the preview-then-confirm flow, which hints at when to call it, but it names no alternatives (e.g. settings_details, customers_create) and gives no explicit when-not-to-use condition. Adequate minimum but with clear gaps.

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