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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint. The description adds behavioral constraints beyond that: headlines only (no body, follow url), no full-text search, no date filter, and the ability to omit ticker for broad market news (though schema mentions this, the description reinforces it). No contradiction with annotations.

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 dense but not excessively long. It front-loads the core purpose and output, then adds limitations and alternatives. Each sentence contributes value, though it could be tightened slightly by merging the ticker/limit clarification.

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 tool with two optional parameters, the description fully covers what an agent needs: output structure, limitations, and alternative tools. The output schema presence is acknowledged, but the description itself specifies the returned fields. No missing information for correct invocation.

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%, so both parameters are documented. The description adds value by explaining how to use limit as a narrowing mechanism given the lack of search/filter, and clarifies ticker's role. It doesn't introduce new semantics beyond the schema but provides usage context.

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 explicitly states the tool returns recent news headlines for a stock, listing the exact fields (title, source, date, url, ticker) in a news array. It clearly differentiates from siblings by noting the absence of full-text search and date filter, and contrasts with get_financial_filings.

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?

It provides explicit guidance: 'Use it for recent coverage of a company you have already identified,' and gives a specific alternative for filings ('use get_financial_filings'). It also explains how to narrow results via limit instead of query, covering when-not and alternatives.

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