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

No annotations are provided, so the description carries the full behavioral burden. It implies a read of shop-defined fields, but does not state permissions, pagination, return shape, or whether inactive fields are included.

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 description is a short, front-loaded fragment with no wasted words. It is structurally terse but efficient, though the missing verb makes it feel more like a label than a complete tool description.

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 two-parameter list tool with no annotations and no output schema, the description should explain return behavior and filtering more fully. It leaves key context, such as output shape and permissions, entirely unstated.

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 0%, so the description must compensate. It indirectly indicates that shop_id scopes results to a shop and that target optionally filters by one record kind, but it does not explicitly name the parameters or fully explain the enum beyond what the schema already shows.

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?

The description identifies the resource as custom fields defined by a shop, but it is a noun phrase rather than a verb-led statement of what the tool does. It does not explicitly say 'list' or distinguish this tool from siblings such as fields_get or fields_define.

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?

There is no guidance on when to use this tool versus alternatives, no prerequisites, and no exclusions. The phrase 'optionally for one kind of record' hints at filtering but does not explain when that filter should be applied.

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