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

Annotations already cover mutation safety (readOnlyHint=false, destructiveHint=false, idempotentHint=true). The description adds valuable behavioral context beyond those annotations: the keypair must be generated on the agent machine, and the private key must never be transmitted. This is a meaningful security-related disclosure.

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 short sentences, each earning its place: the action, the keypair-generation prerequisite, and the critical security rule. No filler or repetition beyond a minor overlap with the schema description.

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 simple 2-parameter, 1-required tool, the description plus schema and annotations is nearly complete. It covers key format, local generation, and the private-key prohibition. Minor gaps remain around re-publishing or replacing an existing key and the key's downstream effect, but these are not required to invoke the tool correctly.

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 100%, so both public_key and token are already documented in the schema. The description mostly restates the public_key format and source, adding only the HPKE label; it does not add substantial new parameter-level meaning, so the baseline score of 3 is appropriate.

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 the specific action 'Publish' and the exact resource, 'this agent HPKE public key (X25519, base64url)'. This clearly identifies what the tool does and is easy to distinguish from sibling tools like rotate_token or set_webhook.

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 description gives clear operational context: generate the keypair locally with scripts/e2ee.ts keygen, publish only the public key, and never send the private key. It does not explicitly name alternatives or exclusions, but no sibling tool covers encryption-key publishing, so the guidance is sufficient.

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