Get Market News

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare the operation as read-only and non-destructive. The description adds important behavioral context by disclosing the FINNHUB_API_KEY environment variable requirement and explaining the default vs symbol-based behavior, which goes beyond what annotations provide.

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 three concise sentences: what it does, the two modes, and the API key requirement. No wasted words, and the most important information 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?

For a simple, read-only news tool, the description covers the essential aspects: purpose, parameter usage, categories, and authentication requirement. No output schema exists, but 'headlines' sufficiently sets expectations for return type. Annotations provide safety context, making this complete.

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 coverage is 100% with both parameters described, so baseline is 3. The description adds extra value by clarifying that category is only relevant when symbol is omitted and explicitly mapping categories to general news, reinforcing the parameter semantics.

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 tool retrieves latest financial news headlines, distinguishing between general market news and company-specific news via symbol. It is specific and distinct from sibling tools which focus on filings, metrics, or other non-news data.

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?

The description provides clear context on when to use the default general news mode versus providing a symbol for company-specific news, and lists valid categories. It does not explicitly compare to sibling tools, but the tool's niche is well-defined and no alternatives for news exist among siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.