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

With no annotations, the description carries full responsibility. 'Publish' implies a mutation, but it does not disclose side effects, whether the operation is idempotent, overwrites existing keys, or requires specific permissions. The security warning is helpful but insufficient to understand the behavioral impact.

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 concise sentences with no filler. The purpose is front-loaded, and the security note is critical and efficiently placed.

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 two-parameter tool with no output schema and no annotations, it provides essential purpose and generation guidance, but omits token semantics and potential side effects. It is adequate for basic use but not fully complete for an agent to call without further clarification.

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?

The description adds meaning for public_key by specifying algorithm and encoding and how to generate it, but entirely ignores the token parameter. With 50% schema coverage, it partially compensates but leaves token undocumented.

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 ('Publish') and resource ('agent HPKE public key'), specifying algorithm (X25519) and encoding (base64url). This clearly distinguishes the tool's purpose from any sibling tool.

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?

Provides a concrete prerequisite: generate the keypair with scripts/e2ee.ts keygen, and a strong security guideline ('Never send the private key'). While it doesn't explicitly name alternatives, it gives clear context on how to use the tool and what not to do.

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