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

The description adds substantial behavioral detail beyond the annotations: the simulation is stochastic, iterations are clamped, probabilities are estimates, and completed matches are locked in via meta.conditioned_matches. It also explains reproducibility via the RNG seed, which annotations do not convey.

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 well-organized with a front-loaded summary, structured Args/Returns sections, and a compact example. Every sentence contributes useful information, and the formatting makes the tool's behavior easy to parse quickly.

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 probabilistic simulation tool, the description covers the tournament structure, parameter constraints, state conditioning, return shape, and example calls. The output schema already exists, and the Returns section adds enough detail for an agent to understand what will come back.

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%, so the schema already documents both parameters. The description adds value with the recommendation that ~10000 iterations gives stable ±2% probabilities and provides concrete usage examples that clarify optionality and seeding.

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 uses a specific verb ('simulates') and a precise resource ('the full World Cup 2026'), and details the full scope: all 12 groups, knockout advancement, and a champion. This clearly differentiates it from siblings like football_simulate_group by covering the entire tournament rather than just one group.

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 intended use is strongly implied by the simulation scope and examples, but the description never explicitly states when to prefer this tool over alternatives such as football_simulate_group or football_knockout_path. It provides clear context but no explicit exclusions or routing guidance.

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