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

With no annotations, the description carries the full burden and does well: it discloses the operation is a priced read (GET /v1/movers/crypto, $0.04 via x402), what is returned (active markets ranked by absolute probability change with volume surge ratios), and the ranking basis. It omits auth/rate-limit behavior, but for a read-only data endpoint the coverage is solid.

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 ranking scope and the differentiator before the metadata block. The bracketed HTTP/price/docs suffix adds useful operational detail but slightly clutters an otherwise tight definition.

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?

No output schema and no annotations, so the description must carry the load: it conveys purpose, cost, endpoint, and return shape ('same shape as /v1/movers'), which is helpful. However, with four parameters at 25% coverage, the absence of limit/category/min_liquidity guidance leaves the definition only partially complete for correct invocation.

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% (only min_liquidity is described), so the description must compensate. It covers just one of four parameters, the window ('over your chosen window,' 1h/6h/24h), and says nothing about limit, category, or min_liquidity semantics, leaving three parameters undocumented in both fields.

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 resource (crypto probability movers), a concrete action/ranking basis (absolute probability change over a window), and explicitly differentiates itself from the sibling probability_movers by being 'pre-filtered to crypto markets.' An agent can tell this apart from probability_movers 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?

Describes when to reach for it: 'The fastest way to see where news is landing in crypto,' and references the parent endpoint ('Same shape as /v1/movers'). It gives clear usage context but names no explicit exclusion or alternative to choose instead for non-crypto or non-mover needs.

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