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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is clear. The description adds behavioral context by stating 'Ordered by popularity,' which informs the agent of the result ordering. It also implies a search behavior (free-text) that is not explicit in annotations. No contradiction exists.

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?

Two sentences with no filler. The purpose and usage are front-loaded, and the example is compact and illustrative. Every word earns its place.

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 simple two-parameter search tool with annotations covering safety, the description is complete. It clarifies the query semantics, ordering, and typical use case. No output schema is present, but the agent can infer the return is a list of series without extra detail. Nothing critical 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 0%, so the description should compensate. It explains q via example ('q='initial jobless claims''), illustrating its use, but does not describe the limit parameter at all. Limit is self-explanatory (a max count), but since coverage is zero, the description leaves a gap. It partially compensates for q but not limit, warranting a mid-range score.

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?

The description clearly states the tool performs a free-text search of FRED's ~800k series catalog, ordered by popularity. It includes a concrete example (e.g., 'initial jobless claims') that illustrates the query type. It distinguishes itself from siblings like fred_series (which likely operates on a known ID) and fred_popular (which may list popular series without search), making the purpose unmistakable.

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 explicitly says 'Use when you don't know the series ID,' giving a clear trigger condition. It does not name the alternative tool (e.g., fred_series) but implies that when the ID is known, a different tool should be used. The guidance is actionable but stops short of explicitly contrasting with siblings.

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