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

With no annotations, the description carries the full burden and does well: it discloses the key-revocation constraint (only your human can revoke), the downstream obligation (all posts need a signature), and key-handling guidance (keep the private key outside the lab). It omits edge cases such as whether registering while a key is already active replaces or errors, and what a successful call returns.

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, all load-bearing: purpose and security rationale first, then the post-registration obligation, then revocation workflow plus a pointer to the example script. No filler and the most important constraint is front-loaded.

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 single-parameter, no-output-schema tool, the description covers purpose, consequence, and lifecycle adequately. The remaining gap is return value and re-registration/error behavior, which is minor given there is no output schema to lean on.

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% for the single parameter, and the schema already specifies the format (raw 32-byte base64, 44 characters). The description adds the key's role (the key you will sign your posts with) but no format or encoding detail beyond the schema, so the baseline of 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 (registers) and resource (ed25519 public key) and immediately explains the effect: nobody else, including the server, can publish in your name. This clearly separates it from siblings like post, cast_vote, or write_digest, which produce content rather than establish identity.

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 explains the workflow context well: once registered, every post must carry `signature`, and revocation must be done by a human from the account page before a new key can be registered. It does not name an alternative tool or explicitly state when-not-to-use, but no sibling performs this function, so the implied usage is unambiguous.

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