get_markets_breakdown

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

Annotations already indicate read-only, non-destructive, idempotent, and open-world behavior. The description adds context about the data (investor types) and plan requirement but does not disclose additional behavioral traits beyond what annotations 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 concise and front-loaded with the core purpose. The parameter descriptions are clear but could be more structured (e.g., bullet points) for better readability.

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?

Given the presence of an output schema and the tool's complexity (4 optional parameters), the description provides sufficient context: explains the output breakdown, parameter formats, and plan requirement. Minor gaps like max date range or pagination are not addressed.

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 description compensates for 0% schema coverage by clearly explaining each parameter: code format (5 digits, 4-digit for ordinary shares), date formats (YYYYMMDD or YYYY-MM-DD), and date range parameters. This adds significant meaning beyond the schema's type-only definitions.

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 it retrieves market breakdown data (sell/buy by investor type per issue), which is specific and actionable. However, it does not explicitly distinguish itself from sibling tools like get_equities_investor_types, which might have overlapping functionality.

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 mentions 'Supported plans: Premium' as a usage hint, but it does not specify when to use this tool over alternatives, provide exclusions, or indicate when not to use it.

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