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

Annotations already mark the tool as read-only and idempotent, so the bar is lower, but the description adds substantial behavioral context: Kalshi fees are not modeled, matching is by token overlap rather than a shared resolution source, temporal_alignment null has specific meaning, and compatibility fields can be non-empty even when matches exist. No statement contradicts the annotations.

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 long but front-loaded with the core purpose and organized under TWO MODES, RESPONSE, SAFETY FIELDS, and code labels. Nearly every sentence carries a distinct fact needed to interpret output safely, especially given the absence of an output schema; the code-list section is dense and could be tightened, but it earns its place.

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 thoroughly documents return contents: leg-by-leg prices, top_spreads_pp, compatibility_codes, temporal_alignment, fees_note, skipped counters, low_confidence_pairs, and per-entry flags. It also covers edge cases such as null alignment, unclassified legs never being paired, and the gross-vs-net fee caveat, leaving no obvious essential gap.

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% and the schema already documents topic values and override behavior. The description adds meaning by explaining that topic mode auto-fetches the mapped event, explicit mode pairs a custom ticker and slug, and both modes run the identical token-overlap matcher with the same disclosures. This is a modest but real semantic increment over the schema.

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 names the resource—the cross-venue spread between Kalshi and Polymarket for the same resolving question—and explains what the tool measures with the 2-25pp participant-pool example. It is slightly weakened by not stating an explicit imperative verb like 'retrieve' or 'compute', and it does not name sibling tools, but the intended function is unambiguous.

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 TWO MODES section gives a clear branch: use `topic` for pre-mapped shortcuts or explicit `kalshi_event_ticker` + `polymarket_event_slug` for custom pairings, and says both modes run the same matcher. However, the description never positions this tool against closely related siblings like `polymarket_arbitrage` or `polymarket_edges`, so alternative-tool selection is left to inference.

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