get_gainers_and_losers

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

Without annotations, the description carries the full burden of behavioral disclosure. It does clarify the mode behavior (today's change vs total return), but it doesn't mention what the output looks like, sorting order, or edge cases. The description is adequate but not rich in behavioral context beyond the obvious.

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 two sentences with the core action front-loaded ('Get the top gainers or losers'). Every word earns its place, and it's appropriately compact for a simple tool.

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?

Despite having no output schema and no annotations, the description is minimal. It describes the main use case and the two modes, but it doesn't mention anything about the return format or how account filtering works. For a tool with three parameters and no output schema, a bit more context would be helpful, but it's not critically incomplete.

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?

The input schema has 100% description coverage, so the baseline is 3. The description reinforces the mode meanings in plain language but doesn't add new information about 'max' or 'accountId'. No redundancy or contradiction, but no added value beyond the schema.

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 tool's purpose: 'Get the top gainers or losers' with a specific verb and resource. It further distinguishes two modes ('by today's change' or 'by total return since purchase'), which is specific and differentiates it from sibling tools like get_portfolio_performance or get_quotes.

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 provides a clear usage guideline: 'Use this for 'best/worst performers'.' This gives a concrete context for when to apply the tool. However, it doesn't explicitly mention when not to use it or name alternative tools, so it falls short of a 5.

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