List predefined Yahoo Finance screeners (e.g., day_gainers, day_losers, most_actives) and get IDs to query market movers via Crawlora MCP.
Yahoo Finance predefined screeners. Lists the predefined Yahoo Finance screeners that can be run, such as day_gainers, day_losers and most_actives, as a screeners list of ids. It takes no parameters. Pass an id to /yahoo-finance/screener/{id}.
| 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?
With no annotations, the description carries the full burden and does disclose the two key behaviors: it takes no parameters and returns a `screeners` list of ids. It could go further (e.g. read-only nature, caching), but for a zero-param listing tool this is solid.
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 tight sentences: identity/scope, output shape with examples, and next-step routing. Nothing is wasted and the purpose is front-loaded.
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?
Covers purpose, absence of parameters, the shape of the return value, and how to consume it, which is enough given no output schema or annotations. Minor gap: no mention of the read-only/safety profile, though that is apparent from 'Lists'.
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?
Zero parameters, so the baseline is 4; the description reinforces this by explicitly stating 'It takes no parameters', which prevents an agent from inventing arguments.
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?
States a specific verb (lists) and resource (predefined Yahoo Finance screeners), gives concrete examples of the ids returned, and the qualifier 'predefined' implicitly distinguishes it from the yahoo_finance_screener_custom sibling.
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?
Clearly frames this as the index/discovery step and tells the agent the next action: 'Pass an id to /yahoo-finance/screener/{id}'. It doesn't explicitly name the sibling tool, but the follow-up path makes the workflow unambiguous.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.