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

Annotations already signal read-only, idempotent, non-destructive, open-world behavior. The description adds useful context beyond that by stating data provenance ('enviroatlas.epa.gov (US EPA)') and explicitly saying 'no auth required.' 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?

Two sentences with no filler. The first sentence front-loads the action and deliverables, and the second compactly adds provenance and authentication context. Every clause earns its place.

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 simple one-parameter, read-only tool with full schema documentation and an output schema present, the description covers the essential context: what it returns, the data source, and authentication requirements. Nothing needed to correctly invoke it 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 100% — the single 'community' parameter is fully documented with examples and a pointer to enviroatlas.communities. The main description adds no additional parameter-level details, so the baseline of 3 applies.

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: 'Get aggregate EPA EnviroAtlas ecosystem-service statistics across all census block groups in an EnviroAtlas pilot community.' It lists concrete metrics (tree cover percent, impervious percent, population, carbon storage, flood-risk population), which clearly differentiates it from community-listing or block-group-level tools.

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 'across all census block groups' phrasing makes clear this is the community-level aggregate view, and the input schema instructs users to call enviroatlas.communities first for the list of valid communities. It does not explicitly name the block_group sibling as the alternative, so it stops short of a 5.

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