get_market_hours

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

With no annotations, the description fully discloses behavior: how is_open is derived (trade_mode), that next_open and next_close are always None in v1, and that precise session boundaries are not available. This is highly transparent.

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 (4 sentences) and front-loaded. The first sentence states the primary purpose, followed by limitations and alternative guidance. Every sentence adds value without 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?

The description covers the main output fields (is_open, next_open, next_close) and their constraints. Given the presence of an output schema and the tool's simplicity, the description is complete.

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 coverage is 0%, and the description adds no detail about the 'symbol' parameter beyond using the term. However, the parameter name and tool context make its meaning clear. The description does not provide additional semantic value.

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 purpose: 'Whether the given symbol's session is open right now.' It uses a specific verb and resource, and distinguishes this tool from siblings like get_quote or get_symbols by focusing on session open status.

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 on when to use this tool (for checking if session is open) and when to use alternatives (for precise session boundaries, consult broker's schedule). It does not explicitly name alternative tools but gives clear usage context.

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