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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds useful context about what information is returned (names, units, descriptions, time range) but does not disclose additional behavioral traits such as response shape nuances or potential edge cases.

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 sentences, no filler, with the core output defined first and a concrete example second. Every sentence earns its place, and the example is directly actionable for an agent.

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?

The tool has one simple parameter, rich annotations, an output schema, and a description that explains both the returned content and the intended usage sequence. Nothing essential is missing for an agent to select and invoke it correctly.

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%, and the single parameter dataset_id is already well documented with examples and cross-references to list_datasets and describe_dataset. The description adds an example value ('nbm_conus') but does not materially expand beyond what the schema already provides; baseline 3 is appropriate.

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 resource (dataset) and a specific purpose: listing available variables with standard names, units, descriptions, and time range. It also distinguishes itself from query_dataset by saying it is meant to discover valid variable names before querying.

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 explicitly says 'Use before query_dataset to discover valid variable names,' giving clear when-to-use guidance and naming the key alternative. It does not enumerate when not to use it or contrast with list_datasets, but the core usage direction is present and unambiguous.

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