Market Hours Grounding Data

Overview

Stock Market Open Times works by querying a large database of stock market open times to retrieve the open times for each day of the week. It returns the stock market open times in a structured format.

Live Test Market Hours Grounding Data Source →

The tool

Once your client is connected to the VerveContext server, this appears in its tool list as MarketHoursGroundingData. It is read-only and open-world — it fetches and never mutates anything on your side — so most clients call it without asking you to confirm.

{
  "name": "MarketHoursGroundingData",
  "arguments": {
    "exchange": "NYSE"
  }
}

You do not name the tool yourself; the model picks it. Asking about NYSE in the terms this source covers is enough for it to reach for MarketHoursGroundingData on its own — naming it explicitly also works, and is the way to force the call.

Connecting

One server URL covers every source in the catalog, including this one. Authorization is OAuth: the client opens a browser once, and there is no key to paste into a config file.

{
  "mcpServers": {
    "vervecontext": {
      "url": "https://api.vervecontext.com/v1/mcp"
    }
  }
}

https://api.vervecontext.com/v1/mcp

Per-client setup — Claude, Cursor, VS Code, ChatGPT — is on the MCP setup page.

Arguments

These are the properties on the tool's inputSchema, so a well-behaved client validates them before the call is made. Premium arguments are accepted on every plan but only take effect on plans that include them.

What the model gets back

The result carries a structuredContent object matching the tool's declared outputSchema, so a client reads fields without parsing prose. status is "ok" and error is null on success; a null field means the value was not available for that input, not that the call failed.

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{
  "status": "ok",
  "error": null,
  "data": {
    "timezone": "America/New_York",
    "exchange": "NYSE",
    "fullName": "New York Stock Exchange",
    "isOpen": false,
    "openingTime": "2025-12-16 09:30:00",
    "closingTime": "2025-12-16 16:00:00"
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Why ground on it

A model can produce something that looks like this answer from its training data, and be confidently out of date or simply wrong. This source returns the current value in a shape you can check, which is the difference between an answer you can cite and one you have to hedge.

Point an evaluation at fullName: it is the field most worth pinning a claim to, and it is either present and current or absent — never plausibly invented.

Failure modes

Errors come back as tool errors carrying a sentence the model can act on, not a bare status code. Error handling covers the full list.

A call costs 2 credits each time the tool actually runs; a model that reasons about the tool without calling it costs nothing.

Use cases

Order Execution Routing

Brokerage systems verify whether a destination market is currently open before queuing or routing limit orders for immediate execution.

Portfolio Dashboard Badges

Financial charting widgets display green or red market status indicators next to asset prices based on the exchange open flag.

Pre-Market Notification Triggers

To alert day traders about upcoming sessions, mobile push services check scheduled opening times and send reminders fifteen minutes prior.

Cross-Border Arbitrage Bots

Algorithmic trading scripts compare overlapping operational hours across international venues like the LSE and NYSE to coordinate hedged positions.

Other ways to use Market Hours Grounding Data

Set up Market Hours Grounding Data on VerveContext, or reach the same source a different way. Your VerveContext account and credits work on all of them — one key, one balance.

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