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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses pricing ($0.002 USDC per successful call), payment rails (x402 on Base, Solana, or Arc), and that failed calls are not charged. That is meaningful behavioral context for a paid data lookup, though it does not cover rate limits or authentication beyond payment.

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 front-loaded with the tool's purpose, then efficiently packs the two view definitions, search behavior, and payment terms into a compact paragraph. Every sentence carries useful information, and there is no filler.

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?

Given an output schema and full parameter-schema coverage, the description is largely complete: it covers purpose, view modes, search, and payment. Minor gaps remain, such as whether free-text search applies equally to credit batches and projects, but they do not prevent correct invocation.

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 schema already documents page, view, limit, and query. The description adds real semantic value by enumerating the returned fields for view=credits versus view=projects and by clarifying that the query is a free-text search over names.

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 opens with a specific verb and resource: 'Gold Standard carbon registry search.' It then spells out the two view modes and the exact fields each returns, which clearly distinguishes this registry-specific tool from sibling registry tools such as Verra VCS, ACR, or CAR.

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?

It explains how to choose between view=credits and view=projects by listing what each returns, and clarifies that query is a free-text search over names. It does not explicitly say when to use this tool over sibling carbon-registry tools, but the registry-specific scope makes the context clear.

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