Get distinct field values

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

Annotations already declare readOnlyHint=true, so the description does not need to reiterate that the operation is read-only. The description adds the behavioral context of being a preliminary discovery tool, but it does not disclose any other behavior (e.g., pagination, limits).

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 two sentences, front-loaded with the action and scope, followed by a specific use case. Every word earns its place; no extraneous information.

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?

Given the presence of an output schema and well-documented input parameters, the description provides sufficient context for a read-only discovery tool. It could be slightly improved by mentioning that the output is a list of distinct values, but the name and title already imply that.

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 high (83%), so the schema already documents most parameters. The description adds the concept of 'over a date range' but does not provide additional parameter-level meaning beyond what is in the schema.

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?

Description clearly states the action 'List the distinct values seen for a column over a date range' and includes a specific use case ('discover valid filter values'). It distinguishes itself from sibling tools by focusing on distinct field values, which is unique among the get_* tools.

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?

Description provides clear context for when to use the tool: 'useful to discover valid filter values ... before filtering other queries.' It implies the tool should be used as a preliminary step, but no explicit exclusions or alternatives are mentioned.

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