List Yahoo Finance sectors with their keys and names, then use a key to fetch that sector's companies, funds, and industries.
Yahoo Finance sectors. Lists the Yahoo Finance sectors, each with a key and a name. It takes no parameters. Use a returned key with /yahoo-finance/sectors/{key} to get that sector's companies, funds and industries.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
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 carries the full behavioral burden. It discloses that the operation takes no parameters and returns objects with 'key' and 'name' fields, which covers the essential behavior for a safe list operation. It does not mention pagination, auth, or rate limits, but those are likely not applicable to this simple root listing.
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?
Three short sentences, front-loaded with identity, then output and parameter facts, then actionable follow-up. Every sentence earns its place with no wasted 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?
Given the trivial schema, no annotations, and no output schema, the description supplies everything an agent needs: it lists what is returned (key and name), confirms no parameters are required, and explains how to use the result to drill into sector details.
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 the baseline is 4. The description explicitly states 'It takes no parameters', which matches the empty schema, but it adds no additional parameter meaning beyond that confirmation.
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?
Starts with a specific verb 'Lists' and the resource 'Yahoo Finance sectors', and adds the output shape (key and name). The follow-up path '/yahoo-finance/sectors/{key}' explicitly separates this root list endpoint from the singular detail endpoint, so an agent can distinguish it from the sibling yahoo_finance_sector.
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?
Tells the agent exactly what to do with a returned key: use it with '/yahoo-finance/sectors/{key}' to get that sector's companies, funds and industries. However, it does not name the corresponding sibling tool or state when to prefer this root list over alternatives like yahoo_finance_industries, so no explicit exclusions are given.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.