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

Annotations already cover readOnlyHint, openWorldHint, and idempotentHint, so the description does not need to restate those. It adds meaningful behavioral context by labeling the tool as a 'Premium API' with a specific cost and payment method ('$0.25 USDC via x402'), which is not captured by the schema or 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 two efficient sentences: the first states the action, resource, and included content, and the second adds the pricing/payment constraint. It is front-loaded with the core purpose and contains 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?

For a single-parameter lookup with strong annotations, the description is sufficient: it names the input type, previews the response content, and flags the cost. It does not describe output format, but that is more acceptable given no output schema and the simplicity of the tool.

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?

The schema owns parameter documentation: 'lookup' is described as 'Company name to retrieve ESG profile for' and includes an example. The tool description adds little beyond repeating that it is for a company, so it does not materially enhance the schema's already-complete coverage.

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?

Description uses the specific verb 'Retrieve' and identifies a clear resource: 'ESG (Environmental, Social, Governance) and sustainability profile for a company.' It further lists the content areas (initiatives, ratings, controversies, reporting frameworks), which distinguishes it from sibling tools like business_info or executive_profile.

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 makes the intended use clear—retrieve an ESG profile for a company—but it does not explicitly state when to choose this tool over siblings or when not to use it. The premium-pricing note adds practical conditions, but routing guidance is only implied by the tool's domain-specific name.

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