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

Annotations already establish that this is a read-only, open-world lookup. The description adds valuable behavioral context beyond that: official source provenance, exact pricing ($0.002 USDC per successful call), supported x402 payment networks, and the fact that failed calls are not charged.

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 front-loaded with the returned data and then moves to input and pricing, so the important information appears early. It is dense and somewhat list-like, but every sentence contributes relevant information and there is little outright 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?

An output schema exists, so the description does not need to explain return values in full, and it still summarizes the profile breadth and recent-bout fields. It also covers payment behavior and the required input, though it could more explicitly route agents away from similar MMA-data siblings.

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?

There is only one parameter and schema description coverage is 100%, with the schema already documenting both fighter name and UFC.com slug formats plus an example. The description repeats the accepted input form but adds no syntax or format detail beyond the schema, so the baseline of 3 applies.

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 a specific resource: a UFC fighter career profile sourced from the official UFC.com athlete page, and it lists the major data returned. It does not explicitly distinguish itself from similar siblings such as dev_ufc_stats, dev_espn_mma or dev_sherdog, so it stops short of a 5.

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 explains how to invoke the tool with a fighter name or slug, but gives no explicit guidance on when to use it instead of similar UFC/MMA data tools. It also provides no exclusions or alternative-tool routing, so usage is only minimally implied.

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