split_aoi

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

With no annotations on the tool, the description carries the full behavioral disclosure burden. It usefully states 'Local computation, no credits' and explains that there is no default maximum cap. It does not describe the output format or potential failure modes, which would be needed for a 5.

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?

Three sentences, each with a distinct purpose: the action, the appropriate use case, and the cap/credit caveats. There is no filler, and the most important information is front-loaded.

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 two-parameter local utility, the description covers the core purpose, when to use it, parameter nuance, and cost behavior. It does not specify the exact return contract, but 'grid of smaller areas' sets a reasonable expectation. A 5 would explicitly state the return payload or edge cases.

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 already documents both parameters with 100% coverage, so the baseline is 3. The description adds value specifically for max_area_km2 by explaining that the cap depends on plan and should be taken from contract or rejection messages. polygon_aoi receives minimal added meaning beyond 'area of interest,' but the overall parameter guidance is improved.

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 a specific verb and resource: 'Cut an area of interest into a grid of smaller areas, each at or under a maximum size you specify.' This makes the function's purpose immediately clear. It does not explicitly name or contrast sibling tools such as validate_aoi, so it stops short of full differentiation.

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 gives an explicit trigger condition: 'Use it when the API rejects an area as too large.' It also provides practical guidance about deriving the max area from the contract or rejection message. It lacks an explicit 'when not to use' or named alternatives, which prevents a perfect score.

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