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

With no annotations, the description carries the full burden. It usefully discloses ranking logic (absolute probability change over the chosen window) and accompanying volume surge ratios, plus the HTTP endpoint and $0.04 x402 price. However it never states read-only safety, rate limits, pagination, or how the passed 'category' parameter interacts with the tool's hard economics pre-filter — a real ambiguity left unexplained.

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 the core purpose in the first clause, then supporting detail. Four sentences are mostly earning their place; the bracketed HTTP/pricing/docs block is meta but practically useful for an agent deciding whether to call it.

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 list tool with no output schema and no annotations, the description conveys what comes back (markets ranked by absolute probability change, with volume surge ratios) and the response shape reference. It still omits pagination behavior, output field details, and the category/pre-filter interaction, leaving gaps an agent would want filled.

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 only 25% (just min_liquidity), so the description must compensate. It clarifies the 'window' parameter by naming 1h/6h/24h and explains the ranking basis, but says nothing about 'limit' or why a 'category' enum exists on a tool already pre-filtered to economics. Partial compensation only.

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+resource with scope: economics prediction markets ranked by absolute probability change. It explicitly positions itself against the sibling by noting 'Same shape as /v1/movers, pre-filtered to economics markets', so an agent can distinguish it from probability_movers and the other probability_movers_* category variants without opening a 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?

'The fastest way to see where news is landing in economics' gives a clear use context for ranking movers after news. It implicitly routes away from the unfiltered probability_movers via the 'pre-filtered' note, but there is no explicit when-not guidance or a named alternative for broader/unfiltered mover queries.

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