List custom fields

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description still adds genuine context beyond that: the required edit_products scope (an auth need) and the native endpoint mapping, plus the 'no local effect approval required' note. Only the 'Read only' clause is redundant with annotations.

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 purpose is front-loaded in the first clause and the whole definition is a compact two-sentence block with no filler. Minor redundancy ('Read only' overlapping with destructiveHint=false) keeps it from a 5.

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 simple read-only list tool with full annotation coverage and 100% schema coverage, the description supplies the key missing operational detail (required scope) and the endpoint mapping. Return format and pagination are unaddressed, but that is minor given no output schema is expected.

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 (account, product_id) are already fully documented in the schema. The description adds no additional meaning about parameter format or the account-vs-product_id distinction, making the correct baseline 3.

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?

Specific verb+resource ('List custom fields') that clearly distinguishes it from the singular get_custom_field and the write siblings (create/update/delete_custom_field). It also maps to the native endpoint GET /products/:product_id/custom_fields, but stops short of naming any sibling it must not be confused with.

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?

The 'scope: edit_products' note implies the prerequisite under which the tool is callable, and 'Read only' implies a safe read path. However, there is no explicit when-to-use vs when-not-to-use guidance or named alternative (e.g., get_custom_field for a single field), so usage is only implied.

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