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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds useful auth/payment context: no API key, no payment, free preview. However, the 'Price 0.01 USDC/query' line sits awkwardly next to 'FREE preview' and could confuse an agent about cost, and the description does not disclose that 'question' is only echoed back.

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 short but repetitive: the no-key/no-payment point is made twice, and phrases like '✅', 'call this now', and 'Try one of the sample questions now' are filler. The useful information is buried in a marketing-style call-to-action rather than presented as a clear tool specification.

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 read-only tool with two optional parameters, the core facts are mostly present across the description and schema: free, keyless, public-metadata-only preview. But the description does not connect this tool to the paid session/query siblings, leaving the agent to infer when a preview is sufficient versus when full data access is needed.

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%, so the baseline is 3. The description adds concrete sample questions for the 'question' parameter, which help an agent understand acceptable input values. It adds nothing about 'slug', but the schema already documents its default and routing behavior.

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 says 'FREE preview' and names a specific listing (fedwatch: US Economic Releases Index), so an agent can infer this is a preview capability. However, it never plainly states the tool's generic function—returning public metadata for a data listing—and the sample questions imply it answers data questions rather than previewing metadata, which weakens clarity.

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 strongly implies a low-risk, zero-setup first step ('No API key needed — call this now', 'FREE preview — no key, no payment'). But it does not explicitly say when to use this instead of data_session_query or data_session_open, nor does it clarify that the preview does not return actual data answers.

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