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

Annotations already declare readOnlyHint=true, and the description adds valuable context beyond that: the underlying data source (CDC NCHS VSRR), the weighting formula (70% trailing-range + 30% year-over-year), the returned components (score, per-cause drivers, direction, confidence, methodology_version), and the quarterly update cadence. This exceeds the baseline set by 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 a single dense sentence that packs essential information: what it returns, data source, methodology, output components, use cases, and update frequency. No redundant words; every clause adds value. It is front-loaded with the core purpose.

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?

Despite having no output schema, the description enumerates the return fields (score, per-cause drivers, direction, confidence, methodology_version) and covers when to invoke the tool. The optional days parameter is fully explained in the schema. The description is complete for a low-complexity, read-only snapshot tool with one optional historical series.

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% because the only parameter 'days' has a detailed description explaining optional history series and Gold tier requirement. The tool description itself does not mention the days parameter, so it adds no additional parameter semantics. Baseline 3 is appropriate since the schema carries the full burden.

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 begins with a specific verb+resource: 'Returns a 0-100 US chronic-disease mortality burden index' and clearly characterizes the index with data source, components, and direction. It distinguishes this tool from siblings by focusing on chronic-disease mortality burden (heart disease, diabetes, stroke), which is not apparent from the generic adw_596 name.

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 includes explicit guidance: 'Call when the user asks about US chronic-disease burden or heart-disease, diabetes, or stroke mortality trends, or when timing population-health, actuarial, or care-market decisions.' This gives clear context, though it does not list when not to use it or name specific alternative tools.

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