flow_accumulation

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

Annotations already mark it as non-read-only, non-destructive, and idempotent. The description adds valuable algorithmic behavior (depressions are filled first) and an environment requirement (whitebox extra), which would not be discoverable from annotations or schema. No contradiction with annotations.

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 compact, front-loads the core operation, and uses linne breaks to separate optional parameter guidance. No redundant or filler sentences.

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 four-parameter raster tool with an output schema and annotations, the description conveys the algorithm, both optional parameters, and a hard dependency. It might not enumerate edge cases or precise path requirements, but nothing essential to selecting or invoking the tool is missing.

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 0%, but the description compensates by defining out_type values ('cells' vs 'sca') and log_transform's purpose. The opening 'GeoTIFF in/out' clarifies dem_path and output_path roles. It doesn't add path-format details, but the parameter names plus these explanations are sufficient.

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 opening sentence names the exact algorithm ('D8 flow accumulation'), the input ('a DEM'), and the I/O format ('GeoTIFF in/out'). This is enough to distinguish it from sibling terrain tools like slope, hillshade, or watershed. The added 'Depressions are filled first' further specifies the computation.

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 clear context: it is for deriving upslope accumulation from a DEM and even notes a dependency prerequisite (whitebox extra). It does not explicitly name alternative tools or state when not to use it, so the agent must infer routing from the tool name and siblings. Overall the context is clear enough, but exclusions/alternatives are absent.

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