Update custom field

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

Annotations already declare destructiveHint=true, idempotentHint=false and openWorldHint=true, so safety is partly covered. The description adds genuinely useful non-obvious context: the OAuth scope needed (edit_products) and that per-call confirmation is mandatory, which is not derivable from the annotations. It still doesn't say what is overwritten or whether the change is reversible.

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 compact sentences, front-loaded with the action before the endpoint and scope details. No filler, though the statement 'Reviewed native PUT ...' is somewhat internal jargon rather than agent-facing guidance.

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 destructive mutation with no output schema, the description supplies the endpoint, required scope, and confirmation obligation, which is most of what an agent needs to invoke it safely. Missing only an explicit statement of the sibling boundary (create/delete counterparts) and the reversibility of the update.

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 all five parameters are already documented in the schema. The sentence 'Requires explicit per-call confirmation' loosely reinforces the purpose of the confirm flag, but no format, encoding, or constraint detail is added beyond what the schema already provides. Baseline 3 applies.

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 ('Update custom field') and pins it to the native endpoint PUT /products/:product_id/custom_fields/:name, which removes ambiguity about what is being mutated. It does not explicitly distinguish itself from sibling create_custom_field or delete_custom_field, so it stops short of a 5.

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?

Mentions the required scope (edit_products) and a confirmation requirement, which implies context, but never states when to reach for this tool versus create_custom_field, delete_custom_field, or get_custom_field. No explicit when-not guidance is given.

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