Exchanges and trading hours

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

Annotations already declare readOnlyHint and idempotentHint, so the description's job is to add context beyond safety. It does this by disclosing that schedules are verbose and omitted by default, requiring an explicit opt-in via includeSchedules. This transparency about default output behavior is valuable and goes beyond the structured annotations.

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 three sentences long, with the first sentence stating purpose, the second giving usage guidance, and the third providing a crucial caveat about verbosity. Every sentence earns its place, and the structure is front-loaded with the most important information. There is no wasted 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?

For a simple list tool with one optional boolean parameter and no output schema, the description is complete. It explains what data is returned, when to use it, and how to control the verbosity of the response. It gives the agent all necessary information to correctly select and invoke this tool.

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 fully documents the single boolean parameter with a description, so baseline is 3. The tool description adds meaningful context by explaining that schedules are verbose and omitted unless explicitly requested, directly clarifying the parameter's purpose and the default behavior. This enhances the schema description and helps the agent decide when to set it to true.

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 returns exchanges and their working schedules, with a specific verb ('Returns') and resource ('exchanges'). It also mentions the time events for session opens/closes, distinguishing it from sibling tools that focus on accounts, positions, or orders. This is a specific and accurate definition.

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 explicit when-to-use guidance: 'Use this to answer whether a market is open, or to explain why an instrument cannot be traded right now.' It does not explicitly mention when not to use it or name alternative tools, but given the sibling tools are unrelated, the usage context is clear and practical.

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