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

Annotations already indicate this is not read-only and not destructive; the description is consistent with those hints. It adds the useful 10,000-row constraint but does not disclose side effects, validation behavior, or failure modes. With annotations covering the safety profile, this is adequate but not rich.

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 a single, front-loaded sentence with no filler. It states the action, object, source, and key limit efficiently.

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 straightforward creation tool with fully documented parameters and an output schema, the description plus schema provides enough to invoke it correctly. The only minor gap is the lack of explicit guidance on what happens if the row limit is exceeded, though the limit itself is stated.

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 input schema provides descriptions for all five parameters, so the description does not need to repeat them. It adds high-level context about parsed CSV rows and the row cap, but no additional per-parameter meaning beyond what the schema already offers.

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 states a specific verb ('Create'), a specific resource ('custom-data dataset'), and the input source ('parsed CSV rows'). This clearly distinguishes it from siblings like create_custom_data_widget, which create widgets rather than the dataset itself.

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 phrase 'from parsed CSV rows' implies when this tool is appropriate, and the 10,000-row limit sets a boundary. However, it does not explicitly name alternatives or state when not to use it, leaving the routing decision to inference.

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