Macro context for the Graham tests

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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely non-structured context: it requires a FRED key (an auth prerequisite) and states that every figure is stamped with the date it applies to. It does not discuss rate limits or error behavior.

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 what is fetched, then the rationale, then the auth/date caveats. Every sentence earns a place — the bond-market rationale justifies why dynamic figures are needed — though the Graham exposition is slightly more than strictly necessary to invoke the tool.

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 carries the return-value burden and does so well: it enumerates the figures returned, notes CPI's TTM change, and that each carries its date. For a single-optional-param read tool this is nearly complete; only the precise response shape and key-handling failure modes are unspecified.

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 single optional priceEarnings param is already defined in the schema. The description supplies the conceptual rationale (the P/E ceiling moves with the bond market) but never references the parameter or its interaction with the fetched yields, so baseline 3 applies.

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 (Fetch) plus a precisely enumerated resource: the Aaa corporate bond yield, the 10-year Treasury, and CPI with its trailing twelve-month change. This is unmistakably distinct from every sibling (etrade_*, congress_*, edinet_*, cache_*), which are account, filing, and cache operations.

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 establishes clear when-to-use context by tying the tool to Graham's earnings-yield-twice-Aaa rule and warning that a book-quoted fixed ceiling applies an outdated bond yield to a current balance sheet. It stops short of naming an explicit alternative tool or a when-not condition, so it does not reach a 5.

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