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

Adds real behavior beyond annotations: the private key is 'returned once and not stored here,' and calls are billed 'paid per call via x402 when payments are on.' This also reconciles the readOnlyHint=true annotation with a 'create' verb, since nothing is persisted server-side. Suite-strength tradeoffs and key format details are left implicit.

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?

Three sentences, each earning its place: what it creates, the one-time private key handling, and the recommended local alternative. The core capability is front-loaded with zero filler.

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 no output schema, the description correctly covers the return semantics (private key handed back once, not persisted) and the cost model, which are the things an agent most needs. It could say more about what else the response contains besides the private key, but nothing required for correct invocation is missing.

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 100% and the single `suite` parameter already documents both X25519+ML-KEM-768 and ML-KEM-1024 (CNSA 2.0) options with a default. The description adds no syntax or selection guidance beyond that, so the schema does the work and 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?

States a specific verb and resource: 'Create a hybrid X25519 + ML-KEM (FIPS 203) key pair for Privi Vault.' The algorithm suite and standard are named, so an agent can distinguish this from vault_open/vault_seal (using existing keys) without inspecting any schema.

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?

Gives clear steering: 'for the strongest setup generate it locally with `python -m privi_quantum.vault keygen`,' which tells the agent when the CLI path is preferable. It also routes cost questions to the quantum_pricing sibling. It stops short of explicit when-not-to-use conditions relative to the other vault_* tools.

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