Polymarket MCP Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions the source of the market parameter but doesn't describe key traits like whether this is a read-only operation, potential rate limits, error conditions, or the format of the returned open interest data. This leaves significant gaps in understanding how the tool behaves beyond its basic function.

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 concise and front-loaded, stating the core purpose in the first sentence. The additional information about the source and example is brief and relevant. However, it could be slightly more structured by separating usage notes into distinct points, but overall, it avoids unnecessary verbosity.

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 lack of annotations and output schema, the description is incomplete for a tool that likely returns numerical or structured data (open interest). It doesn't explain what the output looks like (e.g., a value, units, timestamps) or address potential complexities like handling invalid markets. For a data-fetching tool with no structured output documentation, this is a significant shortfall.

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 input schema has 100% description coverage, with the 'market' parameter documented as 'Market condition ID (0x...).' The description adds minimal value by reiterating this with 'Example: market=0x...' but doesn't provide additional semantics like valid ID formats or constraints beyond what the schema already states. Thus, it meets the baseline for high schema coverage.

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 clearly states the tool's purpose: 'Get open interest for a market.' It specifies the resource (open interest) and the target (a market), which is specific and actionable. However, it doesn't explicitly differentiate from siblings like 'get_market_details' or 'get_market_volume,' which might also provide related data, so it falls short of a perfect score.

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 provides some implied usage guidance by mentioning 'Source: market conditionId from list_markets,' which suggests using this tool after fetching market IDs from 'list_markets.' However, it doesn't explicitly state when to use this tool versus alternatives (e.g., 'get_market_details' might include open interest) or provide clear exclusions, leaving room for ambiguity.

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