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

Beyond the annotations (destructive, idempotent, non-read-only), the description discloses key side effects: deletion is permanent, a namespace_token is required, and the call costs $0.005 in USDC paid via x402 or a credit token. This is exactly the kind of cost and access context an agent needs before executing a destructive operation.

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 compact sentences cover the action, precondition, cost, payment method, and fallback credit path with no filler. The essential destructive action is front-loaded, and every clause adds useful information.

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 rich schema, the annotations (especially destructiveHint and idempotentHint), and the presence of an output schema, the description supplies the important missing context: payment side effects, required auth token, and the free-credit fallback. An agent has enough to decide whether to call this tool and what prerequisites must be satisfied.

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 input schema already documents all four parameters comprehensively at 100% coverage, including the optional credit_token and the nature of the namespace_token. The description adds a helpful pointer to credits_trial for free credit, but it does not substantially expand parameter meaning beyond the schema.

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 opens with 'Permanently delete an item', giving a clear verb and resource, and the title narrows it to deleting a stored secret. This separates it from sibling tools like vault_store and vault_retrieve, leaving no ambiguity about what operation is performed.

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 states the necessary precondition ('Requires the namespace_token') and when an alternative payment path applies ('call credits_trial for free credit if you have neither'). It does not explicitly discuss a when-not-to-use case or name a sibling alternative, but the destructive nature and token requirement provide sufficient context for an agent to invoke it correctly.

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