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

With annotations already declaring readOnly and idempotent hints, the description goes far beyond them: it explains the meaning of compatibility_codes, that unknown metric_type/match_subtype legs are never paired, that temporal_alignment null does not mean aligned, and that spreads are gross because Kalshi fees are not modeled. This is exemplary disclosure of limitations and edge-case behavior.

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 a dense single block of text with many parentheticals, long sentences, and some repetition (e.g., the identical-matcher point is made twice). Every sentence does add information, but the lack of structure (no lists or headings) makes it harder to parse than it could be. It is comprehensive but not concise.

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 (two modes, many safety codes, flags, skipped counters) and the absence of an output schema, the description carries a heavy burden and fulfills it: it explains response fields, warning codes, the fee caveat, and the meaning of temporal fields. Nothing essential for invoking the tool correctly appears to be 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?

Though the schema already covers all three parameters (100% coverage), the description adds substantial meaning: it enumerates the topic shortcuts, explains that explicit parameters override topic-mapped sides, and clarifies that both modes run the identical token-overlap matcher. This goes well beyond the baseline schema 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 specific verb-resource statement: 'Cross-venue spread between Kalshi and Polymarket for the same resolving question.' It then details two modes and the response contents. The tool is clearly differentiated from siblings like polymarket_arbitrage by explicitly naming the two venues and the concept of a cross-venue spread.

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 context on when to use the topic-mode shortcuts versus explicit ticker/slug pairings, and warns that pre-mapped topics often return compatibility_warning and are not necessarily tradeable. It stops short of naming alternative sibling tools or stating explicit when-not-to-use conditions, but the internal routing guidance is strong.

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