market_news

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It clearly states the return format as a JSON string with specific keys, and explains the default behavior for ticker. It does not mention any side effects or rate limits, but for a read-only news fetch, this is adequate.

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 well-structured with clear 'Args' and 'Returns' sections, and is concise without redundant information. Every sentence adds value, and the main 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?

Given the presence of an output schema and three params, the description is complete: it explains all parameters, return format, and default behaviors. It provides enough context for an agent to correctly invoke the tool without needing additional information.

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 description adds significant meaning beyond the schema: it specifies that 'query' searches article titles, explains the optional 'ticker' behavior and its effect on index ETFs, and clarifies the default for 'days_back'. This greatly enhances understanding beyond the raw schema properties.

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 starts with 'Fetch recent market news articles filtered by keyword,' which clearly states the tool's verb (fetch), resource (market news articles), and primary behavior (filtering by keyword). However, it does not explicitly distinguish itself from the sibling tool 'financial_data' beyond the obvious domain difference.

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 how to use the tool, including parameter explanations and the default behavior of 'ticker' when omitted ('scans broad-market index ETFs'). It does not mention alternative tools or when not to use this tool, but the usage context is sufficiently clear.

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