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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds real value beyond that: it discloses the data sources (de-vigged DraftKings/FanDuel moneyline, method and round odds), the modeling approach, and a backtest benchmark (30.9 vs 35.6 points on 2,267 fights), which tells an agent how much to trust the output.

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?

Front-loaded with the core operation ("Monte Carlo simulation (4,000 runs) of every bout on the next UFC card"), and the long output enumeration is dense but each item is a distinct capability. The second sentence on methodology is a run-on but earns its place by grounding the projections.

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, the description carries the return-value burden and does so thoroughly, listing every output family including props and model-vs-market edges. It is slightly incomplete on scope (which card(s), one or many) and does not explain how filters interact, but an agent has enough to call it correctly.

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 description coverage is 100%, so limit, min_ev and fighter are already documented in the schema, which sets the baseline at 3. The description gestures at the edge/EV concept but adds no parameter-specific syntax or defaults beyond what the schema states.

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 gives a precise verb+resource: a 4,000-run Monte Carlo simulation of every bout on the next UFC card, then enumerates the exact outputs (win probability, method, round, distance, props, edges). It never distinguishes itself from near-identical siblings such as invoke_mma_sim_picks, invoke_mma_projections, or invoke_mma_odds, so an agent cannot route between them from the text alone.

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?

There is no when-to-use guidance, no prerequisites, and no named alternative. A reader can infer this is a simulation/edge tool, but nothing tells them when to pick it over invoke_mma_sim_picks or invoke_mma_projections, or that it targets only the next card.

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