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

Annotations confirm read-only/open-world access, while the description adds critical behavior not in annotations: cost ($0.002 USDC), payment mechanisms (x402 on Base/Solana/Arc), and that failed calls are not charged. This is exactly the kind of auth/cost context an agent needs before invoking a paid tool.

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?

Three sentences, front-loaded with scope and output fields, then cost. No filler; the payment sentence is long but carries necessary operational information.

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 simple two-parameter read tool with an output schema and annotations, the description covers scope, exclusions, output fields, and cost. Nothing essential for correct invocation 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 100%, so the two parameters are already documented; the description adds only a single reporter-slug expansion (a2d) and does not clarify the limit parameter. Baseline 3 is appropriate when the schema already 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?

States a specific resource and scope — volume metadata for one reporter — with an example (a2d = Atlantic Reporter, 2nd series) and explicitly excludes case texts, distinguishing it from case-law search tools. An agent can identify the tool's output without opening the 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?

Provides a clear context (one reporter's volume metadata) and a usage boundary ('case texts are not included'), which implies another tool is needed for full case text. It does not name a specific alternative sibling, so it stops short of fully explicit when-to-use/when-not guidance.

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