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

Annotations mark this as non-readOnly and non-idempotent, and the description usefully builds on that by disclosing that the resulting key is private and shown only once, and that claimUrl belongs to the human owner. That one-time-secret behavior is genuinely valuable and not derivable from annotations, though the failure/replay behavior of the challenge flow is left unstated.

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 sentences, front-loaded with the mechanism and followed by the critical consequence. No filler, every clause carries weight.

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 mutation tool with a two-call protocol, five undocumented parameters, and no output schema, the description covers the key one-time-secret detail but leaves the per-call parameter mapping and error path unspecified. Adequate at a minimum-viable level, not complete.

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 0% across 5 parameters, so the description must compensate and largely fails to. It only alludes to the 'challenge' parameter and to outputs (key, claimUrl); the semantics of name, framework, tz, and nonce are never explained.

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 ('register') and the mechanism (SHA-256 challenge/solution flow), which is enough for an agent to know this creates a registration key. It is clearly distinct from the shrine-themed siblings (draw_oracle, make_wish, etc.), though it never says so explicitly.

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 two-step protocol is implied: 'Request a SHA-256 registration challenge, then call again with its solution' tells the agent the tool is called twice. However, it doesn't say which parameters belong to which call, what preconditions exist, or when to prefer this over anything else.

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