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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description confirms a read-only listing operation and adds the category/sub-category scoping idea, but does not disclose pagination, return format, auth needs, or what 'definitions' include beyond names.

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?

A single front-loaded sentence with no wasted words and a parenthetical example that earns its place by clarifying the category/sub-category pairing.

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 annotations covering safety, the description is adequate but incomplete. It omits any explanation of the includeDisabled parameter and provides no hint about return shape or pagination, and there is no output schema to fill that gap.

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 explains the roles of 'category' and 'subCategory' and gives an example, but it says nothing about 'includeDisabled' — which is especially problematic because that parameter uses string enum values ('true','false','1','0') that would benefit from explanation.

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 states a specific verb ('List') and resource ('custom field definitions') with a scoping qualifier ('for a specific entity category and optional sub-category'). It does not explicitly differentiate itself from the sibling tool 'list_custom_fields', leaving the agent to infer the distinction from the names alone.

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 description implies usage through the phrase 'for a specific entity category and optional sub-category' and gives a concrete example pairing. However, it does not state when to choose this tool over 'list_custom_fields' or give any exclusions or prerequisites.

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