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

Annotations already declare readOnlyHint=true, so the safety profile is known. The description adds meaningful behavioral context: the score's data foundation, the fact that updates occur weekly, and the list of output fields. It does not contradict annotations and provides transparency about what the tool returns beyond the read-only hint.

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: two sentences plus an update frequency line. It front-loads the core purpose and returns value, then gives actionable use cases and a concise update note. No filler or repetition.

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?

Given the simple API (one optional param, no output schema, read-only annotations), the description is mostly complete. It covers the score, fields, use cases, and update frequency. A minor gap is that the history series return structure is not explicitly explained beyond the schema's 'daily HISTORY series', but the snapshot fields are listed, which provides adequate context for the common case.

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 input schema has one optional parameter (days) with a thorough description covering behavior, range, and tier requirement. With schema description coverage at 100%, the description does not need to add parameter details. It adds no further meaning to the 'days' parameter, so a baseline score of 3 is appropriate.

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 uses a specific verb ('Returns') and identifies the exact resource: a 0-100 Colorado River Basin water-stress score. It enumerates the output fields (stress_score, supply_pressure, etc.) and context (corporate water-risk disclosures benchmarked against local basin supply conditions, since 2010), which clearly distinguishes it from the many sibling tools in the adw namespace.

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 provides explicit when-to-use guidance: 'Call when the user asks about Colorado River water stress, drought exposure, or water-intensive industry risk, or when timing financing, siting, or capex decisions...' This is clear context. It does not mention when not to use or alternative tools, but the use cases are specific enough to avoid ambiguity.

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