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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: it returns structured items newest first, costs $0.005 USDC per poll via x402 or 2 credits on a sk402_ key, and is a poll operation. It doesn't detail pagination or rate limits, but the cost and ordering info go 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 and front-loaded: it states the primary use case, the alternative, the return format, the cost, and the exclusion in just a few sentences. Every sentence earns its place, and the structure is easy to scan.

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 list tool with annotations covering safety and a schema covering all parameters, the description is nearly complete. It covers the feed types, ordering, cost, and when not to use it. The only minor gap is the lack of an output schema, but the description's mention of 'structured items, newest first' partially compensates. No critical information is missing for an agent to call it correctly.

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 the schema already documents both parameters (signal enum and limit). The description adds the default limit (50) and no upper cap, which is useful, but it doesn't add much beyond the schema. Baseline 3 is appropriate since the schema does the heavy lifting.

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's purpose: fetching the latest items from a curated intel feed, not a one-off URL. It names the resource (curated intel feed) and the specific verb (get/skim signals), and explicitly distinguishes it from sibling tools like skim_read. The title and description align well, and the scope is precise.

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 description explicitly says when to use this tool ('when you need the latest items from a curated intel feed') and when not to use it ('Do not use to read an arbitrary URL'), and names the alternative (skim_read). It also provides a preference over crawling news homepages, giving clear routing guidance.

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