market-movers

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

With no annotations, the description carries the burden of behavioral disclosure. It mentions sources (Yahoo Finance, CoinGecko), that no API key is needed, and the fields returned. However, it omits details on rate limits, caching, error handling, and whether results are real-time or delayed.

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?

Four sentences with no wasted words. The first sentence states the main purpose, followed by source, fields, filters, and use cases. Every sentence contributes essential information.

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 simple retrieval tool with no output schema, the description covers all necessary aspects: purpose, parameters, output fields, and use cases. It lacks examples or output format hints, but it is largely complete.

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 coverage is 100%, and the description adds value by explaining filter options in context, noting that 'active' only applies to equities, and specifying the limit range (1-20). This goes beyond the schema defaults.

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 it returns top market movers for equities and crypto, specifying gainers, losers, and most-active. It names the fields returned. However, it does not distinguish from siblings like crypto-top-movers or market-overview, which could cause confusion.

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 gives use cases (pre-trade context, on-chain event correlation) but does not explicitly state when to use this tool over alternatives or when not to use it. The guidance is implied rather than explicit.

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