distinct_values

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

With no annotations, the description bears full transparency burden. It mentions 'capped' implying a limit but does not specify default behavior (limit defaults to 100) or error handling for invalid columns/tables. Behavioral traits like resource usage or result format are omitted.

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 single-sentence description is concise but overly brief; it front-loads 'distinct values' but lacks logical structure. Every word earns its place, but more detail would improve clarity without adding bulk.

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 tool with 5 parameters and no output schema, the description is incomplete. It does not specify return type (list of distinct values) or how the limit cap works. Contextual details like performance notes or ordering are missing.

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 40% (database and connection have descriptions). The description adds no extra meaning beyond the schema; it does not clarify that 'capped' relates to the 'limit' parameter or explain the role of required parameters (table, column). Given low coverage, description should compensate but fails to.

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 'Distinct values for a column (capped)' clearly indicates the tool retrieves distinct values for a column with a cap (limit). It distinguishes from common siblings like query or count by focusing on distinct values, though not explicitly naming alternatives.

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?

No guidance is provided on when to use this tool versus alternatives such as 'query' with SELECT DISTINCT or 'count' for distinct counts. The description lacks context on preferred usage scenarios.

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