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

With no annotations at all, the description carries the full burden and does disclose a non-obvious and important trait: the private key is returned to the caller and may persist in client histories, which is why testing-only use is recommended. That is exactly the kind of consequence an agent needs before calling. It still omits auth requirements, output format details, and whether generation is deterministic or side-effecting beyond the warning.

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?

The purpose is front-loaded in the first clause, followed by the security caveat. The only waste is that the security warning is stated twice, once in Chinese and once in English, which adds length without adding information.

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 key-generation tool with no annotations and no output schema, the description covers the essential checkpoint — that the returned private key is sensitive and the service is test-only. What remains thin is the return shape (is the CSR and key both returned as PEM?) and the EC-vs-RSA parameter interplay, given only 33% schema coverage.

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 only 33%, so the description must compensate — and it adds partial value by listing the input dimensions (Subject + algorithm + hash + SAN). But it does not explain the RSA-vs-ECC tradeoff, what hash_alg means when algorithm is an EC curve, or how SAN relates to the CN auto-inclusion rule. It also describes SAN as a top-level input while it is actually nested under subject.

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 states a specific verb and resource — generating RSA/ECC private keys plus the matching CSR — and enumerates the inputs (Subject, algorithm, hash, SAN). The purpose is unmistakable and distinct from the decode/match/check siblings, though it never names those siblings 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?

There is a real usage constraint: hosted generation is for testing only, production keys must be generated locally. That covers a 'when not to use' case well. However, there is no routing guidance toward or away from siblings such as csr.decode or cert.match, and no prerequisites or sequencing advice.

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