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

Annotations cover the safety profile (readOnly, idempotent, openWorld, non-destructive), and the description adds substantial context beyond them: data is fetched live per request from nber.org, coverage is mostly 1800s–1960s, and the id-prefix-to-frequency mapping plus fallback resolution order are disclosed. This is richer than the structured fields alone.

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?

Purpose and resource are front-loaded in the first clause, followed by scope, return contents, id conventions, and source. It is dense but nearly every clause carries information; slightly long for a one-parameter tool but no wasted sentences.

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 compensates by enumerating return contents (title, area, units, coverage dates, source notes, and every dated observation). Combined with full param documentation and prefix/fallback rules, an agent has everything needed to call it correctly.

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 baseline is 3, but the description adds meaning the schema does not fully spell out — that m=monthly, a=annual, q=quarterly — giving the agent an interpretive model of the id beyond the schema's format example.

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: returns one NBER Macrohistory series selected by id, and describes exactly what the resource is (NBER's long-run archive of U.S. macro series). It is clearly distinguishable from the sibling nber_macrohistory_list_series, which would serve discovery rather than single-series retrieval.

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 tells the agent what input form is expected (letter-prefixed id, or bare digits with m→a→q fallback), which is practical usage help. However, it never explicitly routes the agent to nber_macrohistory_list_series for discovering ids, nor states when this tool is preferred over alternatives, so guidance 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.