Screener Ratio Lookup

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering safety. The description adds behavioral context: the catalog size (326 ratios) and the distinction between searching and listing. This goes beyond the annotations and helps the agent understand the tool's functionality.

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 two sentences, front-loaded with the primary purpose and immediately followed by usage instructions. Every sentence earns its place with no redundancy.

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 simple tool with one optional parameter and no output schema, the description is complete: it explains what it does, how to use it, and its role in the workflow. It does not describe the return format, but for a lookup tool that is not critical.

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?

The schema description covers q at 100% ('Search keyword... Omit for full catalog.'). The description repeats this with additional examples and the exact count, but does not add fundamentally new semantics. Baseline of 3 is appropriate given full schema coverage.

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: 'Search or list available financial ratios for the screen_stocks tool.' It specifies the verb (search/list), resource (financial ratios), and context (for screen_stocks), distinguishing it from the screen_stocks tool itself. Examples like 'cash flow', 'debt', 'promoter' further clarify the purpose.

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?

It provides explicit guidance: 'Use this to find exact ratio names before building a screen_stocks query.' This tells the agent when to use it, but it does not mention when not to use it or contrast with alternative tools. However, the purpose is so specific that the guidance is sufficient.

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