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

Goes well past the annotations: discloses the data source and model, hard caps (up to 10 articles, past day/week/month), the Brave API redistribution restriction, and pricing ($0.01/call via x402 USDC or card key; failed calls free; repeats charged). The 'reads or computes only and changes nothing' line reinforces rather than contradicts readOnlyHint/destructiveHint.

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-loads what is returned, then limits, caveat, use cases, pricing and safety. Dense but nearly every clause carries information; the sentence structure is packed and somewhat run-on, and 'Not a market signal' reads as an orphaned fragment.

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?

No output schema exists, so the description carries the return contract itself — it enumerates title, URL, publisher, age, per-article score and the aggregate balance. Combined with pricing, quota and freshness limits, an agent has everything needed to call it correctly and to reason about cost.

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 all three parameters are already documented with types, bounds and defaults. The description only adds a sample value (q=bitcoin) and restates the article cap and freshness windows, adding little beyond the schema.

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 composite verb+resource: latest headlines from the Brave News index plus per-article sentiment from a DistilBERT model, plus aggregate balance. The 'in one call' framing distinguishes it from combining `news` and `ai_sentiment`, but no sibling is named explicitly, so differentiation is inferred rather than stated.

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 ('market mood check, brand monitoring or a news brief') and an example query (q=bitcoin), plus a scope caveat ('Not a market signal'). It never names an alternative tool or a case where a sibling (`news`, `ai_sentiment`, `pack_web_research`) is the better pick.

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