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

Annotations already declare that the tool is mutating, non-destructive, and closed-world, so the description does not need to repeat safety basics. It adds useful behavior beyond annotations, including the Pro requirement for weekly schedules, the enter/exit notification toggle, and that last_symbols refreshes the baseline from the live table.

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 the core action and then uses a compact Args section for parameter semantics. Every sentence adds useful information without repetition or filler.

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?

With annotations covering safety and an output schema covering return values, the description supplies the key remaining context for a 7-parameter mutation tool. Its main gap is the omitted strategy_id, though the schema describes that parameter, and it lacks explicit when-not-to-use guidance.

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 only 14%, so the description must compensate, and it does for six of seven parameters: it explains screener_id source, name, query, schedule values, notify_on_change, and last_symbols. It omits strategy_id, but that parameter is documented in the schema itself.

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 states a specific verb and resource: updating a saved screener's name, query, schedule, or baseline symbols. This clearly distinguishes it from sibling tools such as create_screener, delete_screener, list_screeners, and run_screener.

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 implies usage by saying it updates a saved screener and notes that screener_id comes from list_screeners, but it does not explicitly say when to use this tool versus create_screener, delete_screener, or run_screener. The only explicit constraint is that weekly schedules require Pro.

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