fetch_era5_single_levels

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

With no annotations, the description carries the full burden of disclosing behavioral traits. It only states 'Downloads' without mentioning side effects like writing to a local file, requiring network access, or potential authentication/rate limits. The tool's behavior beyond the core download action is opaque, which is insufficient for a data-fetching operation.

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 zero wasted words. It efficiently communicates the tool's core purpose, and no additional content is needed for clarity at the level of intent; other dimensions cover missing depth.

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?

Despite a moderately complex parameter set (8 params) and no annotations, the description fails to provide broader context: it does not explain that it supports spatial bounding boxes, what output format is returned (though an output schema may exist), or how downloads are handled (e.g., file overwrite behavior). The description is too sparse to be considered complete for an agent to confidently invoke the 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?

Schema description coverage is 100%, with each of the 8 parameters having a description in the schema. The tool description itself adds no additional parameter semantics, so it does not improve on the schema. Baseline 3 is appropriate because the schema fully documents parameters, though the description misses opportunities to clarify relationships between coordinates or variable naming.

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 'Downloads ERA5 monthly mean surface data' uses a specific verb ('downloads'), names the exact resource ('ERA5 monthly mean surface data'), and the phrase 'monthly mean' clearly distinguishes this tool from hourly siblings like fetch_era5_hourly_single_levels. It also contrasts with pressure-level and soil-moisture tools, providing clear scoping.

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 implies the tool is for monthly mean surface data but does not explicitly state when to prefer it over alternatives (e.g., hourly or pressure-level tools). There is no mention of when not to use it or which sibling to choose for different temporal/spatial needs, so guidance is only implicit.

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