Run a custom screen

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

Annotations declare readOnlyHint=true and openWorldHint=true, and the description reinforces this with 'Read-only — nothing is mutated.' It also discloses additional behaviors: AND-combination of filters, error handling for unknown fields, and performance characteristics (full-universe scans may time out). No contradiction.

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?

Despite being long, every sentence serves a purpose: scope, safety, return format, field list, units, error behavior, resource pointer, and performance tip. Information is front-loaded with the core purpose first, and no content is redundant with schema or annotations.

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 exists, so the description explicitly explains the return shape (array with ticker, name, price, plus requested metrics). It covers all critical operational details: filters, operators, universe, sorting, error handling, and performance caveats. This is comprehensive for a complex 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 has only 60% coverage, but the description compensates with exhaustive parameter semantics: full list of valid fields, units (decimals, raw USD), sort-only fields, and the 'between'/'in' operator meanings. This adds substantial 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 'Run a custom stock screen' with specific verb and resource, and distinguishes itself from sibling tools like stoquant_run_prebuilt_screen. It is unambiguous about the tool's core function.

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?

Provides explicit guidance on when to use this tool (custom screening vs prebuilt), recommends a specific universe and filter count to avoid timeouts, and names an alternative tool (stoquant_run_prebuilt_screen). This is exemplary usage guidance.

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