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

The description is exceptionally transparent about behavior beyond the annotations. It discloses matching methodology (token-overlap, not shared resolution source), exclusion of unknown metric_type/match_subtype legs, all compatibility_codes and their meanings, the fee schedule omission, and the gross-vs-net caveat. This gives an agent a clear mental model of when results can be trusted.

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-structured with labeled sections (TWO MODES, RESPONSE, SAFETY FIELDS) and every sentence carries substantive information. It is long, but that length is largely justified given the tool's complexity and the absence of an output schema. A small amount of repetition — 'in EITHER mode' and the pre-mapped caveat — keeps it from a perfect score.

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?

Given the tool's complexity, no output schema, and three optional parameters, the description covers everything an agent needs: how to invoke either mode, what the response contains, which safety fields must be read, the meanings of compatibility and temporal flags, fee limitations, and how unclassifiable legs are handled. The repeated emphasis on reading compatibility warnings even when matched_pairs>0 is a valuable safety guard.

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 already 100%, but the description adds real semantic value: it explains that `topic` auto-fetches the matching event on each venue, that the explicit tickers/slugs override the mapped side, and that both modes run the identical token-overlap matcher. It also lists the exact valid topic values, going beyond the schema's enum-free definition.

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 immediately names the exact function: computing a cross-venue spread between Kalshi and Polymarket for the same resolving question. It goes well beyond the title by explaining the two modes, the 10 macro shortcuts, and the response output, leaving no ambiguity about what the tool does. This also differentiates it from sibling Polymarket tools like polymarket_edges or polymarket_arbitrage by its explicit cross-venue scope.

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 description gives clear when-to-use context: use `topic` for pre-mapped shortcuts and explicit tickers/slugs for custom pairings. It also warns that pre-mapped topics often return compatibility warnings and that spreads are gross, not net tradeable edges. However, it does not explicitly name sibling alternatives or state conditions for choosing this tool over them.

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