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

With no annotations, the description carries the full burden and delivers: idempotent lodging ('answered, not repeated'), cross-operator refusal of a key id, the credential required (key), cost (Free) with a 20/hour rate limit, and the governing source (PD8 §10). That is unusually rich behavioral disclosure for a mutation tool.

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?

Front-loaded with purpose and effect; the credential, cost, and rate-limit facts are packed efficiently at the end. The opening sentence has some flourish but every sentence still carries information, so it stays tight.

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?

For a no-output-schema, no-annotation tool, the description covers purpose, effect on the record lifecycle, idempotency, refusal behavior, credential, cost, and rate limit. An agent has everything needed to invoke it correctly and to predict the outcome.

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 all three parameters are already documented in the schema, so the baseline is 3. The description reinforces the private-half-never-leaves guarantee and the lodge/list meaning, but adds little syntax or format detail beyond what the schema already provides.

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 precise verb+resource: lodges the public half of an X25519 vault key, or lists already-lodged keys. It clearly separates itself from nearby siblings like bind_key and notarise by describing the sealing model and the operator-only key custody.

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?

Explains the operative use case (records the Court cannot open) and the downstream mechanics (`held` in place of `content` at POST /api/v1/notarise), plus the lodge-vs-list distinction. It stops short of naming sibling alternatives (e.g. bind_key) explicitly, so it is strong context rather than full routing guidance.

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