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

Annotations already convey the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=true), and the description adds genuinely new context: plaintext is never logged (a privacy guarantee) and the caller must have explicit user intent. It delegates the operation to an external paired signer, which the annotations do not convey. It stops short of describing rate limits or output format.

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 tightly packed sentences with no waste; the purpose leads and the privacy/intent constraints follow. Every clause earns its place.

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 an encryption tool with no output schema and adequate annotations, the description covers purpose, prerequisite, privacy, and gating condition. It could say more about the returned ciphertext or failure modes, but nothing essential 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 low (33%), with only confirm_encryption documented in the schema. The description implies pubkey is a recipient key and plaintext is the input, which adds some meaning, but it never explains the confirm_encryption flag or the 64-hex pubkey format, leaving the coverage gap largely uncompensated.

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 — 'NIP-44 encrypt plaintext for a public key' — and names the mechanism (NIP-44) and the actor (the paired signer). It is immediately distinguishable from the sibling nip44_decrypt and from sign_event.

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 prerequisite ('the paired signer') and the gating condition ('requires explicit user intent') are implied, but no alternatives are named and no explicit when-not guidance is given. Usage is inferable rather than spelled out.

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