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

Annotations already mark it read-only/idempotent/open-world, and the description adds substantial context beyond them: the exact payload fields (source tier, corroboration count, −1..1 sentiment, impact direction, average sentiment label), the 'links only, no article bodies' limit, and a per-call price of $0.002. That is meaningful operational disclosure an agent cannot get from 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?

Front-loaded with purpose and payload, then usage, cost, and routing in a compact block. It is dense rather than padded, though the parenthetical field list is long enough that the sentence strains slightly.

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?

With no output schema, the description carries the burden of describing return contents and does so thoroughly, including the sentiment scale and the 'no article bodies' caveat. Nothing needed to call it correctly is missing.

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 67%, and the description mentions the 'window' concept that maps to the since parameter, but it adds no format or syntax detail for limit or since beyond what the schema already documents. With the schema doing most of the work, this lands at the baseline.

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?

States a specific verb+resource: 'Headlines that touch ONE asset in the window', scoped to a single ticker. It also explicitly distinguishes itself from the sibling filings_for ('for SEC filings use filings_for'), so an agent can separate news flow from filings without opening a schema.

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?

Gives concrete usage contexts ('what is the news flow on X today', 'feed a sentiment gate') and an explicit exclusion routing to filings_for. The 'one ticker' constraint is stated up front, so when-to-use and when-not-to-use are both covered.

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