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

No annotations are supplied, so the description carries the full behavioral burden. It does disclose the metric contents and that the call is free, which is useful beyond structured fields, but it omits whether results are over all time or a window, whether sample sizes are returned, and what happens with no category given (aggregate across all categories vs. error).

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?

One compact sentence with the subject (crowd accuracy) and the three returned metrics front-loaded, followed by the segmentation and the cost note. No filler, nothing that fails to earn its place.

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 one-optional-param, no-output-schema read tool, the description covers what is measured and how it is grouped, which is most of what an agent needs. The remaining gap is the default behavior with no category supplied and the time horizon of the statistics.

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 coverage is 100% and the single enum parameter is fully enumerated in the schema. The phrase 'by category' still adds meaning: it clarifies that category segments the returned metrics rather than filtering rows, which the bare enum does not convey. Small but genuine value beyond the schema.

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-free but concrete resource: the crowd's accuracy expressed as calibration bands, Brier score and favourite-win rate, segmented by category. An agent can distinguish this stats-reporting tool from siblings like arena_leaderboard or market_summary. It stops short of naming a sibling or explicitly saying it is a read-only aggregate report.

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 only implied: an agent should reach for this when it needs to judge how reliable Vatic's crowd forecasts are. There is no explicit when-to-use, when-not, or comparison to alternatives such as arena_leaderboard (who is accurate) versus this (how accurate the crowd is). The trailing 'Free' hints at cost considerations but is not framed as guidance.

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