profile_columns

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

With no annotations, the description carries the full burden. It discloses that the tool scans the whole file (cost), that distinct counts are approximate, and that most-frequent values are only for low-cardinality columns. These are useful behavioral traits. It does not discuss error conditions or permissions, but these are less critical for a read-only profiling tool with an output schema.

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 three sentences plus a clear bulleted Args list. It front-loads the purpose, gives one usage guideline, and then details parameters. Every sentence adds value with no redundancy or fluff.

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 tool has an output schema, return values are covered. The description covers purpose, usage, parameters, and performance (whole-file scan). It is slightly incomplete in not addressing error handling or clarifying the exact output structure, but the output schema mitigates this. Overall it is sufficiently complete for a profiling tool.

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?

The schema has 0% description coverage, but the description's Args section provides meaning for all three parameters: path (file path/glob/URL), columns (restriction, default all), and top_k (number of values, 0 to skip). This fully compensates for the schema's lack of descriptions.

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 opens with 'Profile a file's columns' which is a specific verb and resource, and lists concrete outputs (null counts, approximate distinct counts, min/max, most frequent values). It also differentiates from the sibling tool describe_file by explicitly saying 'prefer describe_file when you only need types.'

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 provides clear when-to-use guidance: it states this tool 'scans the whole file' and directs users to 'prefer describe_file when you only need types.' This gives an explicit alternative and context for when this tool is appropriate.

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