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

With no annotations, the description carries the full burden. It discloses that results come from model training knowledge rather than live lookups, that figures are estimates, and that pay-per-call costs $0.06 USDC via x402 with a specific failure mode when the payment-signature header is missing. It does not cover every possible failure, but the key behavioral caveats and payment requirements are clearly surfaced.

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 with purpose, followed by usage guidance, data caveats, and payment terms. Every sentence adds distinct value; the only minor debit is that payment details could arguably live elsewhere, but with no annotations, their inclusion is justified.

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 the tool's low complexity (two params, no output schema, no nested objects), the description is complete: it explains the return contents, how to use it, the alternative tool, the data-source limitation, and the payment requirement. An agent has enough to call it correctly and interpret results.

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. The description adds context by mentioning 'product category' as the lookup scope, but it does not deepen the agent's understanding of how the optional context parameter affects the comparison. Baseline 3 is appropriate because 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 states a specific verb ('Compare'), a clear resource ('competitor pricing in a product category'), and the exact output items: competitor names, plan tiers, price points, and value-for-money comparisons. It also explicitly differentiates itself from analyze-competitors, which covers strengths, weaknesses, and positioning, so an agent can distinguish sibling tools without opening schemas.

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 explicitly says to use this tool for pricing and packaging decisions, and names analyze-competitors as the alternative for strengths, weaknesses, and positioning. This gives clear when-to-use and when-not-to-use guidance.

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