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

Annotations already mark the tool as readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds valuable behavioral context: it takes a live snapshot rather than historical liquidity, resolves token_id from a market_slug automatically, and notes payment in USDC on Base. No contradiction with 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?

The description is compact but information-dense: the first sentence delivers the core purpose, and later sentences add routing, constraint, and payment context. Every clause earns its place without unnecessary repetition or filler.

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, full schema coverage, and presence of an output schema, the description gives everything an agent needs to select and invoke the tool correctly: purpose, exact input resolution options, the key exclusion, and cost context. No critical gap remains.

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 parameters are already documented. The description adds relationships between parameters, explaining that either token_id or market_slug (+ outcome) is used to resolve the market, and emphasizing that position_size_shares is the size to evaluate for fillability. This goes beyond the schema's individual 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 states a specific verb and resource: it walks a single Polymarket outcome's live order book to determine how much of a position size can be filled, at what average price, and with what price impact. It clearly distinguishes itself from prediction.neg_risk_arbitrage by explicitly excluding multi-outcome basket arbitrage detection.

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 explicitly says when to use the tool: when you need live fill capacity and price impact for a single outcome. It also tells the agent not to use it for multi-outcome basket arbitrage and directs to prediction.neg_risk_arbitrage instead, plus it clarifies exact-slug resolution with no fuzzy search.

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