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

Annotations already cover read-only, idempotent, open-world behavior, so the bar is lower; the description still adds real domain context by defining what an 'open violation' means — not returned to compliance, or not closed out when the system was deactivated. It omits any statement about result-set size limits or pagination, which matters for a search tool.

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, front-loaded with the verb and resource, then output fields, then the has_violation nuance, then the constraint. Slight redundancy in repeating 'drinking water (SDWIS)' twice in the opening clause, but no wasted content overall.

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?

With an output schema and full parameter documentation already present, the description only needed to add domain semantics and invocation rules, and it does both. The one gap is behavior for large result sets relative to the 1–200 limit, which an agent would want to know before calling.

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 coverage is 100%, so baseline is 3; the description goes beyond it by restating the state/zip_code at-least-one rule and by unpacking the has_violation semantics more fully than the schema's one-line note. It adds nothing about limit or pws_type, leaving those entirely to the schema.

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?

States a specific verb and resource — 'Search drinking water systems (SDWIS) by state or ZIP code' — and enumerates the returned fields, so the agent knows exactly what it gets. It doesn't name or contrast any sibling, though the drinking-water domain is unmistakably distinct from the air/facility/superfund siblings, so confusion risk is low.

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?

'At least one of state or zip_code is required' gives a concrete invocation precondition, and the has_violation sentence explains the condition under which the tool narrows to non-compliant systems. It stops short of stating when not to use it or what to do when neither filter is available.

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