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

Beyond annotations (readOnly/openWorld/idempotent), the description discloses how matches are made, that compatibility fields can be non-empty even with matched_pairs>0, that unknown legs are never paired, that null temporal_alignment means uncomputable rather than aligned, that Kalshi fees are not modeled, and that returned codes may include pairing_unverified. It also enumerates specific compatibility codes and skipped-leg counters. 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?

Although long, the description is dense and well-structured with labeled sections (TWO MODES, RESPONSE, SAFETY FIELDS, codes, temporal_alignment, fees, skipped counters). Every sentence adds operational or safety-relevant detail, and the key caveat about pre-mapped not being tradeable is placed at the end for emphasis. The length is proportionate to the tool's complexity.

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 and no sibling guidance, this description carries a heavy burden, and it succeeds: it specifies response shape (leg-by-leg prices, top_spreads_pp, compatibility fields, skipped counters), defines null semantics, discloses fee treatment, and explains which comparisons are excluded. This is complete enough for an agent to know what to expect and what caveats to check.

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 schema already documents all three parameters with 100% coverage, so the baseline is 3. The description adds value by explaining that both input modes run the identical token-overlap matcher, that explicit tickers/slugs override topic-mapped sides, and that pre-mapped topics often yield warnings rather than tradeable spreads. It is slightly less explicit about whether the two explicit parameters may be mixed with a topic, but overall it enriches the sparse property 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 first sentence names the exact operation and resource: a cross-venue spread between Kalshi and Polymarket for the same resolving question. It then distinguishes the tool from other Polymarket-focused siblings by describing the two modes and by warning that pre-mapped topics are not automatically tradeable, so an agent can tell exactly what this tool does.

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 clear usage guidance: choose `topic` for 10 pre-mapped shortcuts or `kalshi_event_ticker`/`polymarket_event_slug` for custom pairings, and explains that both modes use the same matcher and disclosures. It also gives explicit when-not-to-assume warnings (most pre-mapped topics return compatibility_warning; spreads are gross, not net), but it never names or routes to sibling tools such as polymarket_edges or polymarket_arbitrage, so the alternatives dimension is incomplete.

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