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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering safety. The description adds valuable behavioral context: the corner-stamping mechanism ensures probabilities are never matched to the wrong fight, and the explicit note that output is informational, not betting advice, sets expectations. This goes beyond the annotations without contradicting them.

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?

Two sentences with no filler. The first sentence front-loads the core purpose and a key behavioral guarantee; the second adds a necessary disclaimer. Every word earns its place, and the structure is immediately scannable.

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 parameterless tool with no output schema, the description covers purpose, a behavioral nuance, and a usage caveat. The only minor omission is a description of the output format (e.g., list of fights with probabilities), but the name and title strongly imply the return content. Given the simplicity, this is adequate.

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 tool has zero parameters, and schema description coverage is 100% (vacuously). The baseline for no parameters is 4, and the description adds no parameter-specific information because none is needed. No gaps exist 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?

The description clearly states the tool provides 'UFCalendar model win probabilities for upcoming UFC bouts,' with a specific verb and resource. The corner-stamped detail further clarifies the output's association with the correct fight pair. It is distinct from all siblings, as no other tool mentions predictions or win probabilities.

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?

No guidance is given on when to use this tool versus alternatives. The disclaimer 'Informational model output, not betting advice' is a caution, not a usage rule. There is no mention of prerequisites, exclusions, or comparison with similar tools like get_power_index or get_rankings.

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