get_markets_calendar

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

Annotations already declare readOnly, idempotent, and non-destructive. The description adds meaningful behavioral traits beyond annotations: 'All data is returned in a single response without pagination' and the supported plans restriction. It does not contradict annotations, though it omits potential context like response size, timezone, or error behavior.

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 well-structured with a clear one-line summary, then supporting details. There is some redundancy between the first line ('trading days and holidays') and the second line ('trading days, holidays, and half-day classifications'), but overall it remains compact and each section serves a purpose.

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 output schema and annotations, the description covers purpose, parameters, and a key behavioral detail (no pagination). It lacks explicit usage alternatives and date range inclusivity details, but for a read-only calendar tool with a rich output schema, it is sufficiently complete for an AI agent to invoke correctly.

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 input schema has no parameter descriptions (0% coverage), but the description compensates thoroughly. It explains hol_div codes (1, 0, 3) and exact date formats for date_from/date_to, which is essential for correct invocation. This goes well beyond the schema's bare type information.

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 opens with a specific verb phrase 'Retrieve market calendar (trading days and holidays)' and clearly distinguishes it from earnings-oriented siblings like get_equities_earnings_calendar by focusing on trading days, holidays, and half-day classifications. No ambiguity about what resource is accessed.

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 provides context such as 'All data is returned in a single response without pagination' and supported plans, but it does not explicitly state when to use this tool versus alternatives like earnings calendars. Usage is implied by the tool's name and content, but no direct alternatives or exclusions are mentioned, so it falls short of clear guidance.

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