get_market_bookRetrieve a market's current order book and stats by its slug. Use it to inspect live pricing and liquidity before trading on Polymarket US.
Retrieve current market data (order book, stats) for a specific market by its slug
| Name | Required | Description | Default |
|---|---|---|---|
| slug | Yes | Market slug |
Changes observed during successful MCP inspections.
v0.1.0Does 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 a small amount beyond that by naming the returned content (order book, stats) and saying data is 'current', but it does not say whether that means a live snapshot, how deep the book is, or how stale it can be.
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?
A single front-loaded sentence with no filler; the resource and the lookup key both appear immediately. The parenthetical '(order book, stats)' is slightly informal but earns its place by naming the returned payload.
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?
The tool is simple (one required param, annotations present, no output schema), and the description signals the general return content. It falls short on disambiguating from sibling read tools and on describing the shape of the market book, which the missing output schema leaves undocumented.
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?
Only one parameter and schema description coverage is 100%, so the schema already documents 'slug'. The description restates that lookup is by slug but adds no format or resolution detail (e.g. case sensitivity or where to obtain a slug) beyond the schema, matching the baseline 3.
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?
Specific verb ('Retrieve') plus resource ('current market data (order book, stats)') plus an identifying key ('by its slug'). It is clear what the tool does, but it never distinguishes itself from close siblings like get_market_by_slug, get_market_bbo, or get_market_settlement, so the agent must guess which of these returns the book.
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 and no alternative named. The crowded sibling set (get_market_by_slug, get_market_by_id, get_market_bbo, get_market_settlement) makes a routing statement especially valuable, and none is present.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.