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

Annotations provide readOnlyHint=true, so safety is covered. The description adds update frequency ('Updates: hourly'), data sources (GDELT, RSS, CoinDesk), the weighting formula, and history depth to 2015. It also includes the Gold tier restriction via the parameter description, which adds behavioral context beyond 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 compact, front-loaded with the core purpose and output, followed by usage guidance and update frequency. Every sentence provides value, no redundant text, and it fits in two sentences.

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 read-only tool with one optional parameter, the description covers the return fields, sources, update cadence, and usage scenarios. It does not explicitly detail the structure of the 'days' history response, but that is reasonably implied. Given the absence of an output schema, this is sufficiently 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% (only 'days' well-described). The description does not add further parameter semantics beyond what the schema already provides. The baseline of 3 applies since the schema fully documents the parameter and its behavior.

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 returns a '0-100 global news sentiment and trend velocity index' with specific details on sources, weighting, and history. It lists exact output fields (sentiment_index, news_velocity, tone_score, source_diversity_score), distinguishing it from any sibling tool. The verb 'Returns' is specific and the resource is unambiguous.

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?

Explicitly defines when to call: 'Call when the user asks about news sentiment, media tone, news-flow spikes, breaking-news momentum, or headline risk' and even extends to trading applications. It lacks explicit exclusions or named alternative tools, but the context is clear and actionable.

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