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

readOnlyHint=true already declares the safety profile, so the description's added value is the return shape (name, type, dropdown choices) and tenant scoping. It does not mention pagination behavior or the effect of the embed parameter, though the schema covers those.

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 verb and resource, followed by the one usage hint that matters. Nothing redundant.

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, the description does describe the returned fields, which is the key need for a read-only listing tool. Minor remaining gap: it does not mention paging or the grouped-vs-flat effect of embed, though the parameter schema documents both.

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 page, embed and per_page are already fully documented in the schema. The description adds nothing about them, which is the baseline 3 case where structured data does the heavy lifting.

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 a precisely scoped resource: 'List the definitions of the tenant's custom employee fields,' and even enumerates what a definition contains (name, type, dropdown choices). This cleanly distinguishes it from sibling list tools such as smarthr_list_employees, which return records rather than schema definitions.

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?

'Use them to read the values in custom_fields' gives a concrete when-to-use condition tied to interpreting employee data. It stops short of naming an alternative or stating exclusions, but the context for calling it is clear.

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