Look up an ISIN from a Yahoo Finance ticker symbol using an experimental yfinance-compatible lookup and return the result as structured JSON.
Yahoo Finance ticker ISIN. Returns the experimental yfinance-compatible ISIN lookup result for a symbol.
| Name | Required | Description | Default |
|---|---|---|---|
| symbol | Yes | Yahoo Finance symbol such as AAPL |
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 full burden. It labels the result as 'experimental' (hinting at instability) but does not disclose error behavior, rate limits, or authentication needs. The output format is vaguely described as 'yfinance-compatible'.
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 with no superfluous text. The first sentence serves as a title, the second adds context. Efficient, though could be more structured.
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 single-parameter tool with no output schema or annotations, the description is minimal. It lacks details on return shape, error conditions, and integration context (e.g., how ISIN results are typically used).
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% (symbol parameter well-documented). The description adds context about the output nature but does not enhance parameter meaning beyond what the schema provides. Baseline 3 is appropriate.
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 it returns an ISIN lookup result for a given symbol, distinguishing it from other yahoo_finance_ticker_* tools by specifying 'ISIN' and 'experimental yfinance-compatible'.
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 guidance on when to use this tool versus other lookup/search tools in the sibling list (e.g., yahoo_finance_lookup, yahoo_finance_search). The description does not mention alternatives or exclusion criteria.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.