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

Annotations give readOnlyHint=true, and the description goes beyond this by disclosing that this is an approximation with false positives and misses, that prices are corporate-action-adjusted but not dividend-adjusted, that US history starts 2023-03-28, and that empty results should not be treated as errors. It also explains the 'database has not been built yet' error condition.

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 front-loaded with purpose, uses clear section headers, and is scannable with bullets. However, the Args section largely duplicates the input schema, and the approximation caveat is repeated several times. These are minor, since each section still earns its place.

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 10-parameter, 0-required-parameter tool with an output schema, the description is complete: it documents all strategy conditions, parameter semantics, output shape, examples, data quirks, error behavior, and when to route to alternative tools. There is no meaningful operational gap for an agent deciding how to invoke this tool.

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%, so the baseline is 3. The description adds value by mapping parameters to the strategy conditions, giving concrete examples (e.g., min_price=10 for US$, 5000 for KRW; min_vol_avg20=500000), and showing how arguments combine in practice. It loses a point because the Args block mostly restates schema defaults and the market arg listing omits the 'tw' enum option that the schema supports.

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 opens with a specific verb and resource: 'Screen KR, US and/or TW stocks for a Marty Schwartz short-term momentum setup.' It names the strategy logic, the data snapshot, and the approximation nature. It also disambiguates itself from siblings by directing to screen_minervini for the trend template and screen_kell for EMA-support leaders.

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 an explicit 'Use when' section: short-listing short-term momentum names on a 10-EMA green light. It gives concrete exclusions ('Don't treat a pass as a Schwartz buy') and names which siblings to use instead for other strategies. It also includes practical examples for US liquid names and tight KR setups.

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