Determine if a Yahoo Finance market, such as US, is open or closed by supplying the market code.
Yahoo Finance market status. Returns Yahoo Finance open/close status for a market such as US.
| Name | Required | Description | Default |
|---|---|---|---|
| market | Yes | Market such as US |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must disclose behavioral traits. It only says 'returns open/close status' but does not mention authentication needs, rate limits, error handling, or what happens for invalid markets.
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?
Extremely concise: two short sentences front-loading the purpose. No unnecessary words.
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 tool with one parameter and no output schema, the description provides the essential purpose and an example. However, it does not specify the output format (e.g., boolean or string) or clarify what 'status' includes.
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 description coverage is 100%, baseline 3. The description adds 'such as US' as an example but does not enumerate valid markets or provide format details. Adequate but minimal.
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 verb 'returns' and the specific resource 'Yahoo Finance open/close status for a market such as US'. It distinguishes from sibling yahoo_finance_* tools by focusing solely on market open/close 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?
No explicit guidance on when to use this tool versus alternatives like yahoo_finance_market_summary or yahoo_finance_ticker_quote. The description merely states what it does without context for selection.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.