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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds valuable behavioral context beyond annotations: the FRED_API_KEY requirement, the source attribution, and the fact that frequency aggregation is available via parameters.

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?

The description is well-structured and front-loaded with the core purpose, followed by concise use-case bullets and parameter guidance. Every sentence earns its place, and there is no redundant restating of the tool name or title.

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 fetch tool with an output schema and safety annotations, the description is largely complete: it covers purpose, usage context, key parameters, API key requirements, and source. It does not explain every schema field, but the core FRED workflow is sufficiently specified.

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?

With schema description coverage reported at 0%, the description must compensate for parameter meaning. It does explain observation_start/observation_end and frequency, and implies series_id by referencing 'a specific economic series' and SearchFredSeries. However, it leaves limit, series_id as an explicit parameter name, and the many generic fin params (wholesaler_ids, source_resource_id, etc.) unexplained in the description itself.

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 opens with a specific verb and resource: 'Fetch time-series observation data from FRED for a specific economic series.' It also states the return shape ('date + value pairs with series metadata'), and explicitly routes users to SearchFredSeries when the series ID is unknown, distinguishing it from the sibling search tool.

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 provides a clear 'Use this tool when' list covering macro data needs, macro context, cross-period comparisons, and current indicator values. It also names SearchFredSeries as the alternative for unknown series IDs, though it does not explicitly list when-not-to-use cases against other siblings.

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