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

With readOnlyHint/idempotentHint already covering safety, the description adds valuable behavioral detail: null order books instead of fabricated prices, not_found for unknown identifiers, billing semantics, payment-challenge behavior on unpaid calls, and no settlement when no data is returned. This goes well beyond the annotations and helps an agent anticipate edge-case responses.

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 yet information-dense: purpose, use case, edge-case behavior, billing, and an HTTP route equivalent are conveyed in three sentences. No sentence is filler, and critical caveats are placed early.

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?

For a read-only lookup tool with no output schema, the description sufficiently describes output contents (outcome pricing, best bid/ask, midpoint, spread, top price levels with sizes) and covers errors and costs. An agent has enough information to invoke the tool correctly and interpret its likely responses.

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 coverage is 100%, with each parameter (id, slug, condition_id, depth) already having descriptions and examples. The description repeats identifier options but adds no new parameter-level detail, so a 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?

Description opens with a specific verb-resource pairing: 'One Polymarket market' retrievable by Gamma id, slug, or condition id, and distinguishes itself by including 'full outcome pricing and the LIVE CLOB order book'. This clearly differentiates it from sibling tools like polymarket_markets and polymarket_trades, which cover lists and trade history.

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?

It says to use it 'before taking a position, to see real depth rather than only a last price,' which gives a clear use context. It does not explicitly name alternatives or state when to use them, so it falls just short of the strongest guidance.

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