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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds valuable context beyond that: data source (FRED PAYEMS), calculation formula (recent job growth vs trailing-mean % deviation), historical depth (monthly since 1942), update frequency, and output field names. No contradictions with annotations.

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 sentences, each earning its place: output and method, when to use, and update cadence. No wasted words or redundant restating of the tool name/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?

The tool is well-specified for its complexity: one optional parameter fully documented, read-only annotation present, and output fields listed in the description despite the lack of an output schema. Minor gap: no explicit description of the default snapshot's structure beyond field names, but this is not a critical omission.

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 single optional parameter 'days' is fully described in the input schema (100% coverage), including its range, purpose, and Gold-tier requirement. The description itself does not expand on parameters, but the schema already carries the load, and the 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?

The description opens with 'Returns a 0-100 US nonfarm-payrolls momentum score', using a specific verb and naming the exact resource and metric. It also explains the FRED PAYEMS methodology and lists output fields, making it clearly distinguishable from generic sibling tools.

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 states when to call: 'Call when the user asks about US job creation accelerating or slowing, employment growth, hiring momentum, payrolls, or labor-market strength', plus broader macro forecasting use cases. It does not mention when not to use it or point to alternatives, but the guidance is concrete.

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