list_screeners

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

Annotations already mark it idempotent and read-only. The description adds valuable context: the exact count (24), return shape, and caching hint. 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?

Three sentences, zero waste. Purpose first, then usage guidance, then return format. Perfectly structured.

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 parameterless list tool with no output schema, the description covers everything: purpose, usage, return shape, and caching behavior. Completely sufficient.

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?

No parameters exist, so the description's job is minimal. It still clarifies the output structure, earning a baseline 4.

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?

Clearly states it returns metadata for all 24 stock screeners, specifying fields (slug, name, description, category, tier). Distinguishes from sibling get_screener_data by positioning as a discovery step.

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?

Explicitly advises to use before get_screener_data and to call once per session due to rare changes. No alternative tools needed for listing screeners, so guidance is complete.

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