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

Annotations declare readOnlyHint=false and destructiveHint=false (a safe write), and the description adds valuable context beyond that: the axis is catalogue-wide, not product-scoped, and should be confirmed with the merchant first. It does not disclose what happens on a duplicate axis name (error vs. merge), leaving one behavioral gap.

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 sentences, front-loaded with the core action, followed by the routing condition and the merchant-confirmation caveat. No sentence is redundant.

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-required-parameter create tool with no output schema and full schema coverage, the description covers purpose, routing, and global-scope impact well. The only missing piece is the failure/duplicate-handling behavior, which is minor.

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%, so both parameters (name, values) are already fully documented with examples in the schema. The description only alludes to "name and values" without adding syntax or format detail, so the baseline 3 is appropriate.

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: "Create a new variation axis with its possible values." It also names the sibling hub_get_product_options, so an agent can distinguish this create tool from the read tool without opening either 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 gates usage: "Use it only when get_product_options shows nothing suitable" and directs the agent to "reuse an existing axis when one fits." Both the when-to-use and when-not-to-use conditions are stated, with the alternative named.

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