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

Annotations already declare read-only, idempotent and non-destructive, so the safety profile is free. The description adds real behavioral value beyond that: it discloses that the tool returns x402 REST terms rather than executing anything, and explicitly that it 'does not pay or score over MCP' — a critical distinction in an ecosystem containing kit_buy_x402.

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?

Two tight sentences, front-loaded with the action and result, then the key negative constraint. No filler; both sentences earn their place.

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?

No output schema exists, and the description partially compensates by naming the return ('x402 REST terms'). But with zero parameter documentation and an undefined return shape, an agent still lacks enough to construct or consume the call confidently, even for a one-parameter 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?

Schema coverage is 0% for the single required 'bundle' parameter, so the description carries the burden; it names the expected type ('commonrig.doctor.bundle/1'), which is a genuine hint about the payload format. However it says nothing about how the bundle is supplied or structured, leaving a real gap for the only parameter.

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 verb (Validate) and resource (a commonrig.doctor.bundle/1 bundle) and says what it returns (x402 REST terms for a hosted footprint check). Sibling differentiation is indirect — it distinguishes itself from payment/scoring tools via 'Does not pay or score over MCP' rather than naming kit_buy_x402, but an agent can still tell it apart. The domain jargon ('hosted footprint check') is opaque to an outsider.

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 clause 'Does not pay or score over MCP' gives negative guidance that implicitly routes payment intent to kit_buy_x402, which is useful. But it never states when to call this tool versus kit_quote, kit_describe, or kit_sample, so the positive usage condition (validating a bundle before a footprint check) must be inferred.

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