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

Annotations only declare readOnlyHint and openWorldHint; the description adds substantial behavior beyond that — it buys opposite sides at equal whole-contract size, walks current ask depth, includes estimated taker fees and conservative Kalshi rounding, emits candidates only when all-in cost is below the common payout, and critically warns results are unfilled non-atomic candidates requiring both exact-size legs to fill. That non-atomicity/liquidity caveat is exactly the kind of context annotations cannot carry.

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 action and dense with no filler sentences, each carrying real semantics. It is somewhat long and runs several clauses together, which is why it sits just below the top mark, but no sentence is wasted.

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 return-value explanation is unnecessary, and the description still covers the execution model, caveats, filters, and the alternative tool. Nothing needed to call it correctly is missing.

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 both parameters are already documented in the schema — family as a key returned by the tool, max_capital_usd as capital across both legs. The description reinforces family's origin 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?

States a specific verb+resource+scope: scanning fingerprint-pinned Polymarket–Kalshi equivalent pairs for two-leg coverage arbitrage. It explicitly distinguishes itself from the sibling list_executable_opportunities by naming the single-side alternative, so an agent can route without opening either schema.

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?

Gives explicit when-to-use routing: use this tool for two-leg coverage, and use list_executable_opportunities 'to find the cheaper venue for buying a single side.' The condition that selects each tool is stated outright, not implied.

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