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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so safety is well covered. The description adds useful behavioral context: it searches a corpus of 800,000+ series, returns IDs and titles, and ranks by popularity. It doesn't disclose pagination or the result shape, but the annotations and moderate complexity make this a solid score.

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 first sentence states what the tool does, the second explains when to use it. 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?

With schema covering 100% of parameters and annotations covering mutability/idempotence/read-only safety, the description is nearly complete. The only gaps are the resulting payload structure and behavior when no results are found, but since there is no output schema and this is a search/discovery tool with known caveats, a 4 is fair.

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%, with each of the 4 parameters already described in the schema (search_text, search_type, tag_names, limit). The description adds the ranking-by-popularity context and the example use case, but doesn't significantly expand on parameter semantics beyond the schema. Baseline 3 applies because the schema carries the documentation load.

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 full-text search across FRED's 800,000+ economic series and returns matching series IDs and titles ranked by popularity. It also explicitly identifies the use case: when you don't know the exact series ID.

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 says to use this tool when you don't know the exact series ID, which gives clear selection guidance. Among FRED siblings, fred_series_info, fred_observations, fred_category_series, and fred_quick_indicator serve different purposes; this description explicitly frames its use case for discovery rather than retrieval of a known series.

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