screen_market

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

No annotations are provided, so the description carries the full transparency burden. It discloses that presets run against the full ~6,000-ticker universe using bulk data 'cheap on quota', explains the behavior of each screen type, and notes the special 'list' mode for the catalog. It could be more specific about output format (e.g., fields returned) but this is not required given the output schema absence.

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 well-structured with clear sections: purpose, usage triggers, a bulleted screen type list, and Args/Returns. It front-loads the primary purpose in the first sentence and every subsequent line carries useful information without redundancy. The length is justified by the number of screen types.

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 4-parameter tool with no output schema, the description is fairly complete: it covers purpose, when to use, parameter semantics, and returns. It could describe the output structure in more detail (e.g., symbols, metrics), but the provided 'Stocks matching the screen criteria' is adequate for a screening tool. It also mentions the catalog fetch via screen_type='list', which is a critical edge case.

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 0%, but the description fully compensates by explaining every parameter in the 'Args' section. It defines screen_type (with a complete list of valid values plus the catalog option), limit, min_market_cap (including dollar default and server default), and exclude_earnings_days semantics. This adds meaning beyond the bare 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 function with a specific verb+resource: 'Screen the market for trading opportunities.' It enumerates 11 distinct screen types and explicitly distinguishes its scope from sibling tools by listing when to use it (e.g., 'Finding trading opportunities', 'Unusual activity scan'). This differentiates it from other screening tools like scan_volatility_arb.

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 includes a dedicated 'Use this tool when the user asks about' section listing concrete scenarios, which provides clear usage context. However, it does not explicitly state when NOT to use this tool or name alternatives, so it misses the 'exclusions' part of a 5.

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