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

Beyond annotations, the description discloses the paid nature and flow: 'Buy a $1.00 USDC comparison' and 'Uses x402; the first call returns payment requirements.' This explains the financial side effect, which aligns with destructiveHint=true, and adds context about the payment protocol.

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 three sentences: purpose, use cases, and payment behavior. It's front-loaded with the main action and no redundant words.

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?

With an output schema present and clear payment flow, the description covers the essential workflow: buy a comparison, provide slugs, first call gets payment requirements. It doesn't explain the output details, but that's covered by the output schema. It also doesn't mention if the comparison is cached or real-time, but that's not critical for tool selection.

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 only parameter companySlugs is fully described in the schema: 'Two to four unique reviewed company slugs returned by get_exviv_catalog.' The description adds no further parameter-specific instructions, so it relies on the schema's 100% 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?

The description states 'Buy a $1.00 USDC comparison of reviewed plans, prices, limits, features, source URLs, capture dates, and historical changes across two to four software competitors.' This clearly identifies the action (buy), resource (comparison), scope (2-4 competitors), and differentiates from siblings like get_company_pricing which focuses on a single company.

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 provides explicit use cases: 'Use for product marketing, deal support, procurement, and positioning decisions.' However, it does not mention when not to use or alternatives, so no exclusions or sibling differentiation.

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