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

Annotations declare destructiveHint=true, and the description goes well beyond that by explaining the money impact (compounding on a running total, reordering changes what customers pay), the non-retroactive scope ("Sales already rung up are NOT recalculated"), and the exact-input constraint that rateIdsInOrder cannot add or remove rates. This is the kind of consequence detail an agent must have before invoking a destructive mutation.

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-loads the three things the tool does, then layers the consequence, the input constraint, the alternative tools, the merchant-confirmation rule, and the retroactivity caveat. Every sentence is functional, though the all-caps emphasis and length make it denser than strictly necessary.

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 4-parameter, no-output-schema mutation with destructiveHint, the description covers inputs, consequences, prerequisites, and alternatives completely enough to call correctly. It does not address failure modes (e.g. a nonexistent or mismatched taxGroupId), which is the only notable 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, but the description adds real meaning: it clarifies that taxGroupId must come from get_taxes rather than a name, and that rateIdsInOrder is a strict permutation of existing rates with no additions or removals. These restate the intent behind the terse schema descriptions rather than adding new syntax, so it lands just above baseline.

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 specific verbs and resource up front (rename a tax group, make it the standard one, change rate charging order), which lets an agent distinguish it from hub_update_tax_rate and hub_create_tax_group. It also explicitly distinguishes itself from the add/remove siblings in the same domain.

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 an explicit prerequisite ("Takes the tax group id from get_taxes, never a name"), explicit exclusions routed to named alternatives ("Use add_tax_rate_to_group / remove_tax_rate_from_group for that"), and an explicit confirmation requirement before reordering or setting the standard group.

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