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

Annotations already declare readOnly/idempotent/openWorld/non-destructive, so safety is covered. The description adds real behavioral context beyond that: the GAF is CMS's own published figure (not an estimate), it carries a 1.0 floor, a state returns all its localities, and years 2024-2026 are loaded.

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?

Front-loads the core question and answer, then layers examples, sourcing, and routing. It is somewhat long with repeated locality examples, but nearly every sentence earns its place by clarifying behavior or routing.

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?

An output schema exists, so return values needn't be described. Combined with full schema coverage and annotations, the description supplies everything an agent needs: what it returns, how to name localities, year range, and how it relates to sibling tools.

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 the baseline is 3, but the description adds meaning beyond the schema: the locality-vs-city distinction, that a bare state returns all localities, and that omitting year yields the newest loaded year. This is genuinely useful disambiguation the schema alone doesn't convey.

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: returns the CMS FQHC PPS GAF for a locality/year plus the GAF-adjusted per-visit rate. It explicitly distinguishes itself from siblings medicare_fqhc_pps_rate (national base rate) and medicare_gpci_lookup (underlying GPCIs), so an agent can route without opening a schema.

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?

Gives concrete trigger examples ("FQHC PPS GAF for Orlando, Florida 2025") and names the alternative tools it complements. It also states a key usage constraint: a city is not a locality, so the caller must name a locality or pick from the list.

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