Polymarket Agent Mcp

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

With no annotations provided, the description carries full burden but lacks critical behavioral details. It mentions 'Pro feature' (access restriction) and 'sparkline visualization' (output format), but doesn't disclose rate limits, authentication requirements, data freshness, error conditions, or whether this is a read-only operation (though implied by 'Fetch').

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 appropriately sized with three concise sentences. It front-loads the core functionality, adds output details, and ends with access information. No wasted words, though the 'Pro feature' could be integrated more smoothly.

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 2-parameter tool with full schema coverage but no annotations or output schema, the description is moderately complete. It covers purpose and output visualization but lacks behavioral context (rate limits, auth, errors) and doesn't fully compensate for missing output schema details about the price points structure.

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%, providing complete parameter documentation. The description adds minimal value beyond the schema, mentioning 'configurable time window' which aligns with the interval parameter but doesn't provide additional semantic context about parameter interactions or constraints.

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 specific action ('Fetch historical OHLC price data'), resource ('for a market token'), and scope ('over a configurable time window'), distinguishing it from siblings like markets.price (likely current price) or analysis.compare (comparative analysis). The mention of sparkline visualization further differentiates its output.

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 implies usage when historical price data with visualization is needed, but provides no explicit guidance on when to use this tool versus alternatives like markets.price (current price) or analysis.compare (comparative analysis). The 'Pro feature' note hints at access restrictions but doesn't clarify functional alternatives.

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