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

Annotations already establish readOnlyHint=false and destructiveHint=false, so safety is partly covered. The description adds genuinely useful behavioral context: the group charges nothing until rates are added, no product uses it until assigned, and the isStandard default caveat — all beyond structured fields. It doesn't cover permissions/auth or what the call returns, keeping it 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?

Front-loaded with the core action and definition, then workflow guidance. Every sentence carries a distinct instruction (definition, prerequisite, lifecycle, isStandard caveat, confirmation). Slightly dense but no filler.

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 2-param create tool with no output schema, the description covers purpose, prerequisites, side effects, and the risky parameter. It doesn't indicate what the caller gets back (e.g., the new group's ID), but with no output schema that is a minor omission.

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. The description adds real semantic weight beyond the schema: isStandard is the company default and should only be set on explicit merchant instruction, and the name must be confirmed with the merchant before calling.

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+resource and defines what a tax group actually is ("a tax profile that products get assigned to") with examples. It clearly differentiates itself from siblings like create_tax_rate, add_tax_rate_to_group, and update_tax_group by describing the object and its lifecycle.

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?

Explicit sequencing ("Call get_taxes FIRST"), an explicit warning about the duplicate-meaning failure mode, and named alternatives for the follow-up actions (create_tax_rate, add_tax_rate_to_group). It also states when NOT to set isStandard ("only if the merchant explicitly says so").

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