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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds the cost signal ($0.015 USDC), which is useful context, but it does not explain the masked/unmasked gating behavior or how the paid unlock flow works beyond what the schema already says.

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?

It is a single run-on sentence that front-loads the core purpose but is heavily keyword-stuffed ('Unified ... Aggregator and Cross-Venue Probability Spread / Arbitrage Scanner'). It is compact but the noun-piling reduces clarity rather than earning each word.

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 annotations fully cover the safety profile and the schema fully documents all four parameters (including the paid-unlock flow), the description is complete enough for an agent to decide and invoke. No output schema exists, but return masking is described in the schema, so nothing critical is 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?

Schema description coverage is 100%, so the schema already documents query, limit, x_api_key, and payment_signature fully. The description adds no parameter-level meaning (no syntax, ranges, or interaction notes), so the baseline 3 is appropriate.

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 states a specific action (aggregating prediction markets and scanning for cross-venue probability spreads/arbitrage) across named venues (Kalshi, Polymarket, Manifold). This is clearer than a tautology, but it never distinguishes itself from the sibling 'prediction_markets' or 'perp_funding_arbitrage', so an agent cannot easily tell which scanner to pick.

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?

There is no when-to-use or when-not-to-use guidance. With a sibling named 'prediction_markets' and another arbitrage scanner ('perp_funding_arbitrage'), the description should explain what situation selects this tool, but it offers nothing beyond a label.

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