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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds useful context beyond annotations: input flexibility (4-digit zero-padding), coverage (3,144 counties), and the exact nature of returned data. This is meaningful additional transparency without contradictions.

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 purpose, then return details, then input quirks and coverage. Every sentence earns its place with no filler or redundancy.

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 no output schema, the description thoroughly enumerates all major return components: composite score, label, ranks, 5-domain breakdown, key findings, and citations. It also addresses input formatting and availability, making it complete for a single-parameter read-only tool.

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 schema description already provides 100% coverage for the single 'fips' parameter, including a detailed example and zero-padding behavior. The description repeats this information but does not add new semantic meaning beyond what the schema states, so the 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 ('Fetch') and identifies a unique resource ('County Distress Index (CDI) scorecard') keyed by FIPS code. It distinguishes itself from sibling tools like get_indicator or get_adi_composite by detailing the composite score, domain breakdown, and citations it returns.

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 clearly indicates the tool is for fetching a full county scorecard and specifies input format ('5-digit FIPS', '4-digit FIPS with implicit leading zero'). It does not explicitly state exclusions or alternatives, but the context makes it apparent this is for county-level aggregate data rather than individual indicators.

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