Which of the world's stock exchanges are open right now (or at a given time)? Returns every tracked exchange with its open flag and status — ideal for "which markets are trading?".
| Name | Required | Description | Default |
|---|---|---|---|
| at | No | Optional ISO 8601 timestamp to evaluate AT a specific moment (e.g. "2026-07-06T14:30:00Z"). Defaults to now. Use it for "will the NYSE be open at 3pm ET on Monday?". |
Changes observed during successful MCP inspections. Dates show when Glama detected each change.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnlyHint=true and idempotentHint=true. The description adds that it returns an open flag and status for every tracked exchange and can be used at a given time, which is useful context beyond 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?
Two sentences, no unnecessary words, and front-loaded with the core purpose. Every sentence adds value.
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 is sufficient for a tool with one optional parameter and no output schema. It covers purpose and parameter usage, but could briefly mention the return format (list of exchanges) for complete clarity.
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 explains the 'at' parameter with format, default, and an example query ('will the NYSE be open at 3pm ET on Monday?') adding significant meaning beyond the schema.
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 all tracked exchanges with open flag and status for a given time, which differentiates it from siblings like is_market_open or get_exchange_status that focus on individual exchanges.
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 suggests ideal use for checking which markets are trading and mentions evaluating at a specific time, but does not explicitly state when not to use it or compare to sibling tools for more specific queries.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.