market_status

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

With no annotations provided, the description carries full responsibility for behavioral disclosure. It gives specific, non-obvious details: the exact status values (open/pre_market/after_hours/closed) and the UTC-time basis of the calculation. It omits potential nuance like holiday handling, but for a read-only, no-parameter tool this is strong coverage.

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?

Two tight sentences with no filler. The first front-loads the core purpose and scope, and the second supplies the output vocabulary and time basis. Every sentence earns its place.

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 tool with no parameters, an existing output schema, and a read-only nature, the description covers all needed facts: purpose, exact market scope, returned statuses, and the time reference. Nothing an agent needs to decide whether to call it is missing.

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 tool has zero parameters, so schema coverage is trivially 100% and the description needs to document no arguments. It does add semantic context by naming the fixed markets (US, HK, CN) it covers. Baseline 4 for a parameterless tool is appropriate.

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 states a specific verb and resource: 'Get global market open/close status for US, HK, and CN markets.' It clearly identifies the exact data returned and the three market scopes, making it easy to distinguish from quote- and kline-focused siblings.

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 implies when to use this tool—whenever global market session status is needed—but it does not explicitly mention sibling alternatives like market_summary or state when to prefer one over the other. This leaves some routing to inference, though the purpose is clear enough to avoid gross misuse.

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