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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered structurally. The description adds meaningful behavioral context beyond that: the required FRED_API_KEY environment variable, the exact return fields (series ID, title, frequency, units, seasonal adjustment, date range), and the upstream source. It does not discuss rate limits or result caps beyond the schema's max.

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 the core action and return shape, then structured with a when-to-use list and a scannable series-ID table. Slightly longer than strictly necessary given the annotations already signal a safe read, but every section carries usable content.

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 an output schema present, return values need not be explained, and the description still summarizes them plus the auth prerequisite. The one gap is that the schema exposes several unrelated parameters (wholesaler_ids, exclude_fillers, source_resource_id, mcp_prompt_id, question_asked) that the description never mentions or reconciles, which could confuse an agent.

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?

The description adds no direct parameter documentation, but the schema's nested properties already describe query, limit, and order_by well, so the baseline is 3. The 'Common series IDs' list indirectly illustrates the kind of keyword the query parameter accepts, which is a modest supplement rather than a substitute for parameter docs.

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 (Search) and resource (FRED economic data series by keyword), and explicitly distinguishes itself from the sibling GetFredSeriesData by naming it as the follow-up step. An agent can tell what this tool does and how it differs from the fetch tool without opening either schema.

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?

Contains an explicit 'Use this tool when:' block listing three concrete scenarios (finding a series ID before fetching, discovering available macro data, gathering macro context for financial analysis), plus a direct pointer to GetFredSeriesData for the next step. Nothing is left to inference.

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