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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so the safety profile is covered. The description adds a useful data-exclusion constraint (no secrets/contacts/files), but says nothing about pagination, ordering, or what 'authorised' means operationally, and 'through the existing application' is vague.

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?

Two short sentences, front-loaded with the core action and followed by scope limits. 'Through the existing application' is slightly filler, but overall there is no bloat.

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?

With no output schema and zero parameter descriptions, the description should carry the burden of explaining pagination limits, query semantics, and return shape. Instead it only states the resource and exclusions, leaving the agent without enough to call it precisely.

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% for the three parameters (limit, query, offset) – only types and defaults are given. The description does not mention any of them, leaving the meaning and behavior of 'query' and pagination entirely undocumented.

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 (read) and resource (custom field definitions) with a data-scope qualifier ('authorised', 'metadata/approved fields only'). It does not distinguish itself from close siblings such as list_custom_field_sections or get_custom_field_reporting_metadata, so an agent must infer the boundary.

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 exclusion clause ('no secrets, contacts or original files') implies this is for metadata-only access, but there is no explicit when-to-use guidance and no reference to the sibling tools that list sections or reporting metadata. Usage is inferable but not directed.

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