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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuinely non-obvious behavior beyond that: it discloses update cadence (every business day) and, importantly, the blank-value semantics — a blank means the official BLS/BEA release has landed and the model stops estimating. Rate limits and caching are not mentioned, but this is a solid supplement.

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 what and the source, then the disambiguation, then return shape, then the null-value caveat — a sensible ordering. The three quoted example queries are slightly redundant with each other, but each sentence otherwise carries information.

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?

There is no output schema, so the description has to describe returns, and it does: MoM and YoY for current and prior month, plus quarterly annualized for current and next quarter. Combined with the cadence and blank-value explanation, an agent knows exactly what it will get back and how to read gaps.

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?

Zero input parameters, so baseline is 4. The description reinforces this by saying the source is 'keyless' and carries no user-supplied arguments; nothing further about parameters is needed or missing.

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+resource ('Daily CPI and PCE inflation nowcasts, headline and core') with the producing institution named. It explicitly disambiguates from the nearest sibling cluster by saying 'keyless, NOT a FRED series', which routes the agent away from fred_get_series, and the inflation-vs-GDP split separates it from nyfed_gdp_nowcast.

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?

Offers concrete activating queries ('current CPI estimate before the official release', 'PCE inflation nowcast today') and the keyless/no-FRED-key constraint, which is the main selection condition against FRED siblings. It stops short of an explicit exclusion ('do not use for historical CPI series — use fred_get_series'), so the routing is implied rather than stated.

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