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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds real behavioral context beyond them: this is a per-DAY encounter rate not a per-procedure fee, it is the pre-GAF national base, and CMS publishes only one number a year. It omits auth/rate-limit details, so not a 5.

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-loaded with the core question and the answer definition, and the sibling disambiguation is well separated. It is somewhat long, with several example phrasings ("what is the FQHC PPS base rate", "how much does Medicare pay an FQHC per encounter") that partially duplicate the opening statement.

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, one optional parameter, and annotations covering safety, the description fully conveys what is returned (a single national base rate figure), its scope, its limits, and the sibling to use for adjusted rates. Nothing needed to call it correctly is missing.

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%, and the description largely restates the schema: omit year for newest year plus full history, pass year for one row. The parenthetical that the history is small adds minor meaning but does not go beyond the schema enough to lift the baseline.

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?

Specific verb+resource+scope: it returns the CMS FQHC Prospective Payment System national BASE rate for a calendar year. It explicitly distinguishes itself from medicare_physician_payment, medicare_lab_rate, and medicare_fqhc_gaf, so an agent can disambiguate without opening any 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?

Names the alternative and the exact condition that selects it: for the GAF-adjusted amount in a named locality, use medicare_fqhc_gaf. It also tells the agent when to omit year (newest loaded year plus full history) versus pass year (one row), so invocation is unambiguous.

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