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

With readOnlyHint already declaring the operation safe, the description adds substantial behavioral context: fixed whitelists mapped to SQL predicates with parameter-bound thresholds, nightly refresh behavior, corporate-action adjustments, US data history limits, empty-result semantics, and known error strings. This far exceeds what annotations alone provide.

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 long but highly structured and information-dense: Args, RS explanation, Returns, Examples, Use when, Notes, and Errors each serve a distinct purpose. It is front-loaded with the core purpose and safety property, and no sentence is 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?

For a tool with 8 parameters, an output schema, and several siblings, the description covers all relevant context: market scope, signal semantics, sorting, filtering, output format, use cases, exclusions, known limitations, and error behavior. An agent has everything needed to invoke it correctly without further research.

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?

Although the schema already has high coverage, the description enriches every parameter group: it defines signal thresholds, explains sort-key semantics, and describes rs_pctile/rs_120d in practical terms. The worked examples also clarify parameter combinations and expected usage patterns beyond the raw 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 action and resource: screening companies by technical signals on the latest indicator snapshots. It distinguishes itself from relevant siblings by explicitly naming get_technicals for one-company detail and screen_companies for fundamentals. The action and scope are specific and unambiguous.

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 'Use when' section explicitly says to use this tool for ranking/filtering many companies by momentum or trend signals, and directly tells the agent not to use it for one company's detail or fundamentals, even naming the alternatives. This gives clear selection criteria without requiring inference.

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