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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds value beyond that: the per-call cost ($0.002/call), the universe size (~500 most active open markets), and the fact that results include bid/ask and spread. It does not cover pagination or rate limits, but for a read-only search this is a strong disclosure.

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?

Front-loaded with what the tool does and its scope, then the return fields, then filters and price, then the routing hint. The inline field enumeration is dense but earns its place since there is no output schema. Minor redundancy in restating the search dimensions twice, which is why it is not a 5.

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?

With no output schema and 0% schema description coverage, the description compensates by enumerating the response fields (id, slug, question, yes_prob, best_bid, best_ask, spread, change_24h, volume, liquidity, end_date, url) and pricing. The remaining gap is the undocumented limit parameter and filter value formats, which keeps it from a 5.

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 0%, so the description must carry the parameter burden, and it does list the filters q, tag, ends_within_days and min_liquidity with their intent. However, it says nothing about value formats (units for ends_within_days, whether q is free text or exact match) and it omits the limit parameter entirely, so an agent cannot infer result capping from the description.

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?

States a specific verb and resource ("Search the ~500 most active open Polymarket markets") with scope (open, most active, ~500) that an agent can act on directly. It also names the sibling it is not ("for the top list use polymarket_top"), so the agent can distinguish it from polymarket_top and polymarket_events without opening either schema.

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?

Explicitly says when to use it: search by words, tag, closing date or liquidity, and when to use the alternative polymarket_top for the top list. It stops short of stating exclusions, such as when to prefer polymarket_events or polymarket_context, or that closed or resolved markets are not covered.

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