Issue a scoped, expiring, offline-verifiable capability credential (PAID $0.05)

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

Annotations already declare readOnlyHint=false, idempotentHint=false and openWorldHint=true, so the write/non-idempotent profile is covered. The description adds genuinely useful context beyond that: the exact price (0.05 USD), the payment rail (x402/base/usdc on eip155:8453) and the HTTP route. It does not say what an issued credential persists, whether issuance is recorded/side-effecting, or how payment failure manifests.

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 short lines with no filler, and the purpose statement is front-loaded ahead of the payment/route detail. Slight deduction because the first line merely repeats the title verbatim, so the space is not fully earned.

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 full schema-description coverage, the description need not explain return values, and it does cover purpose, cost and route. It nevertheless leaves gaps an agent needs for a paid, non-idempotent issuance operation: wallet/payment preconditions, and when this tool is the right choice among ~100 siblings.

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% and every parameter carries a substantive description (scope vocabulary enforcement, max_uses range, ttl range, policy_ref hash implication). The description adds nothing about parameters, so the baseline 3 applies.

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 names a specific verb and resource ('Issue a ... capability credential') and qualifies it with three meaningful properties (scoped, expiring, offline-verifiable). However, it is essentially a verbatim restatement of the title and gives no differentiation from the large sibling set (e.g. v1_identity_agent_attest, v1_mandate_compliance), so it falls short of a 5.

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?

There is no guidance on when to use this tool versus alternatives, no stated prerequisites beyond the price, and no exclusions (e.g. when to prefer an attestation or identity tool instead). The only situational information is the payment cost, which is context rather than usage guidance.

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