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

With no annotations, the description carries the full burden and does reasonable work: it discloses the auto-resolution/roll-forward behavior so the agent knows the answer always targets the next occurrence, names the added response fields (current_slug, rolls_to_next_at), and surfaces the $0.02 x402 payment requirement. It omits caching/rate-limit behavior, but the dynamic semantics are well covered.

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 core question is stated twice ('Live probability: Will the Fed hike rates at its next FOMC meeting?' then 'Stable evergreen URL for a recurring question: Will the Fed hike rates at its next FOMC meeting?'), which is pure duplication. The metadata footer is compact and useful, and the behavioral sentence earns its place, but the redundant restatement is waste.

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 no output schema or annotations, the description supplies the essentials: what the value represents, how it rolls forward, the extra response fields, and the access/cost model. It is close to complete for a zero-parameter read tool, with only minor gaps around failure/caching behavior.

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?

Zero input parameters, so the baseline is 4. There is nothing parameter-level for the description to clarify, and it correctly does not invent parameters.

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 states a specific verb+resource (live probability for a Fed rate hike at the next FOMC meeting) and defines a narrow, self-differentiating scope. It implicitly separates itself from the sibling probability_evergreen_fed-next-meeting-cut via the 'hike' framing and from probability_get via the 'stable evergreen URL', though it never names those alternatives.

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?

Usage is implied rather than stated: the recurring-question/evergreen framing suggests this is for tracking the rolling next-meeting outcome rather than a fixed market instance. There is no explicit when-to-use vs when-not or a named alternative (e.g. probability_get for a pinned instance), so the agent must infer routing.

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