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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds only the returned field list, which is redundant with the output schema, and says nothing about Finnhub rate limits, API key requirements, or behavior when no articles match.

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?

Two sentences plus one example, with the core purpose front-loaded and no filler. The example is slightly redundant with the input schema's examples array but is short enough to earn its place.

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 single-purpose read tool with full schema coverage, an output schema, and four annotations, the description covers enough to invoke it correctly. The remaining gaps (rate limiting, empty-result behavior, symbol validation) are minor for this complexity level.

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% and all four parameters are documented in-schema with formats and examples, so baseline 3 applies. The description's example merely restates the schema examples plus the undocumented _apiKey parameter implicitly, adding no new semantic detail.

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 ('Get recent news articles about a company') bounded by a date range, and enumerates the returned fields. It is clearly distinct from siblings like company_facts or get_quote, but never explicitly contrasts itself with them.

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 inline example shows a valid call shape, which implies intended usage, but there is no statement of when to prefer this over company_facts, get_quote, or recent_alerts, and no exclusions or prerequisites (e.g. symbol must be a valid ticker, news coverage windows).

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