Retrieve an ETF's expense ratio, category, AUM, NAV, fund family, and inception date using its ticker symbol.
Get detailed fund info for an ETF: expense ratio, category, AUM, NAV, fund family, and inception date.
| Name | Required | Description | Default |
|---|---|---|---|
| symbol | Yes | ETF ticker symbol (e.g. VUG) |
Changes observed during successful MCP inspections.
v1.3.1Does 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 lists output fields but does not disclose data freshness, whether this is a read-only lookup, response shape, or any limitations. The agent can infer it is a read operation from the name, but the description adds little beyond that.
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?
The description is a single sentence that fronts the action and resource, then efficiently enumerates the returned fields. Every word earns its place, and there is no redundant filler.
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?
This is a simple one-parameter tool with no output schema, so the field enumeration in the description meaningfully conveys what the agent should expect. It is adequate for invocation, though it would be stronger with a note distinguishing it from quote or performance tools.
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 schema already fully documents the single parameter 'symbol' with an example ('VUG'), so schema coverage is 100%. The description adds no additional semantic detail about the parameter, but the baseline of 3 is appropriate because the schema does the heavy lifting.
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 names a specific action ('Get detailed fund info') and resource (ETF), and enumerates the exact fields returned: expense ratio, category, AUM, NAV, fund family, and inception date. This is clear, but it does not explicitly distinguish itself from siblings like get_etf_quote or get_etf_performance, so it misses the top score.
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?
There is no guidance about when to use this tool versus the sibling tools. The sibling names imply alternatives, but the description never states that this is the best choice for static fund profile data rather than quotes, holdings, or performance, leaving the agent to guess.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.