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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, which fully covers the safety profile for a pure calculator. The description adds 'profitability' framing but nothing beyond that. The stray 'Returns: {lose_probability}' is redundant given a full output schema exists, so it neither adds nor contradicts.

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 short sentences with the purpose front-loaded. The 'Returns: {lose_probability}' fragment is slightly noisy, but overall the text is tight and free of padding.

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 simple pure-calculation tool with a full output schema and annotations covering the safety profile, the description is largely sufficient. The main shortfall is the absence of any routing guidance among the many probability/odds siblings, which is minor relative to the calculator's self-contained nature.

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 the meanings of win_probability, win_amount, loss_amount, and bet_cost are already documented in the schema. The description adds no unit, range, or interpretation detail beyond what the schema provides, which is the expected baseline when the schema does the heavy lifting.

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 and resource: 'Calculate expected value and profitability of a bet or investment decision.' An agent knows what computation is performed. However, it does not differentiate from nearby siblings like calculate_lottery_odds, calculate_poker_hand_probability, or calculate_dice_probability, leaving some ambiguity about which probability tool to pick.

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 only guidance is 'See list_bundles for related jeux-probabilites calculators', which points at a browsing tool rather than explaining when to use this calculator versus alternatives. There is no statement of when-not to use it or which sibling covers adjacent scenarios.

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