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

Annotations already declare the full safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is low. The description adds that it returns observations for each series, a useful return-shape hint, but says nothing about truncation, alignment of differing frequencies, or rate limits.

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?

Three tight sentences with the core action front-loaded and no filler. The use-case sentence is slightly illustrative rather than essential, but overall the structure is efficient.

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?

For a read-only tool with full schema coverage and annotation-provided safety profile, the description covers the action, scope and return hint. No output schema exists, so the brief return note is sufficient, though alignment/pagination behavior is left implicit.

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%, so series_ids, start, end and limit are all documented in the schema. The description restates the 2-to-5 bound and shared date range but adds no new parameter semantics such as frequency alignment or default range behavior, 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?

States a specific verb and resource (compare FRED series) and quantifies the scope (2 to 5 series, same date range). This clearly differentiates it from the single-series siblings like fred_observations and fred_series_info, though it never names those alternatives.

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?

Provides motivating use cases ('ratio analysis (e.g. compare 10Y vs 2Y yield) or cross-series correlation'), which helps an agent recognize the right scenario. However, it gives no explicit when-not-to-use guidance and doesn't point to the singleton fred_series_info/fred_observations tools for the non-comparison case.

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