list_indices

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

Discloses data source ('Scrapes the indices overview page') and explains nullable fields (name, isin) when server-side profile missing, beyond the readOnlyHint annotation.

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?

Few sentences, front-loaded with purpose, efficiently conveys key usage and behavior without superfluous text.

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 output schema present, description still adds value by explaining return fields and null behavior; covers main logic and edge cases well.

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 covers limit parameter 100%; description adds minimal extra meaning ('Returns up to limit indices') but no new semantic detail beyond what schema provides.

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?

Description specifies 'List the BVB index universe' with concrete examples (BET, BET-TR) and distinguishes from sibling get_candles by showing how the output is used.

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 a clear use case (list indices) and explicitly connects to get_candles for charting, but does not contrast with other siblings like list_instruments.

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