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

Beyond readOnly and idempotent annotations, the description discloses key behavioral traits: the matcher is keyword/word-overlap based and never pairs legs with unknown metric_type or match_subtype; spreads are gross because Kalshi fees are not modeled; temporal_alignment null means 'could not be computed,' not aligned; and compatibility_codes can be non-empty even when matched_pairs>0. This is exemplary disclosure of limitations.

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 into labeled sections and front-loads the core purpose, but it is very long and contains redundancy, such as restating that temporal_alignment_unknown means the resolution month could not be parsed and that null is not equivalent to alignment. Every sentence is informative, but the text could be tightened without loss of meaning.

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 carries the full burden of explaining the response, and it does: it lists leg-by-leg prices, spread array contents, compatibility fields, skipped counters, fees_note, and temporal_alignment semantics. It also sets expectations about the rarity of real spreads. Nothing needed for correct use appears 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?

The input schema already describes all three parameters with 100% coverage. The description adds semantic value by explaining that topic is a pre-mapped shortcut, that the two explicit parameters override the topic-mapped side, and that both modes run the identical token-overlap matcher. This goes beyond the schema's basic field descriptions.

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 opens with a clear statement of what the tool does: 'Cross-venue spread between Kalshi and Polymarket for the same resolving question.' It names the two venues, the quantity produced (spread), and the condition for validity (same resolving question), which distinguishes it from single-venue siblings like polymarket_edges.

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 explains when to use each of the two modes (topic shortcuts vs explicit event ticker) and how the explicit parameters override the topic mapping. It also warns that most pre-mapped topics return compatibility_warning today, setting expectations. However, it does not explicitly contrast this tool with sibling tools like polymarket_arbitrage or state when not to use it in favor of an alternative.

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