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

Annotations already cover the safety profile (readOnly, non-destructive, openWorld), but the description adds genuinely new operational facts: the call costs 5 credits, an empty slate is free and returns a note explaining why, and a failed call is also free. Cost and failure semantics are exactly the kind of behavior an agent cannot infer from annotations alone.

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?

Purpose and scope are front-loaded in the first clause, and the sentences are information-dense rather than padded. The empty-slate sentence is slightly knotty in phrasing ('An empty slate costs nothing, and a note says why...; so does a failed call'), but every sentence carries load-bearing information.

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-field detail is already covered, so the description rightly spends its budget on scope, cost, empty-state and failure behavior. An agent has everything needed to decide whether to call it and what to expect.

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 parameters, so the baseline is 4 and there is nothing for the schema to document. The description confirms 'takes no arguments' and clarifies the implicit scope (current slate only), which is the only semantic worth adding here.

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+resource ('the model's win probability for each NHL game on the current slate') and enumerates exactly which fields come back (home/away probability, A/B/C grade, start time, model version, generation time). It distinguishes itself from siblings like get_odds by explicitly saying no odds or prices are included.

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?

Clear about the operative constraint ('takes no arguments, current slate only') and about what is not covered (odds, prices, goalie/injury notes), which implicitly routes the agent to get_odds or get_game_detail for those. It never names an alternative tool explicitly, so it falls short of a full when-to-use/alternative mapping.

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