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

No annotations are provided, so the description carries the full burden. It discloses the ciphertext length requirement (key_size/8 bytes), the need for matching padding mode, and the output format. These add behavioral context beyond a simple 'decrypt' statement, though it does not discuss failure modes or side effects.

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 description is tightly structured with sections for purpose, parameters, and output. Every line contributes valuable information, and the most important fact (decryption) is front-loaded. No wasted words.

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?

Given the complexity of RSA decryption with multiple padding modes and optional password, the description covers the essential inputs, constraints, and output. It does not describe error handling or elaborate on key size, but for a decryption tool with no output schema, this is a solid, complete overview.

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%, so baseline is 3. The description adds meaningful detail for each parameter: PEM format for the key, hex format and length constraint for cipher_data_in_hex, the requirement that padding mode match encryption, and the conditional use of password. This enhances understanding beyond the schema.

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 explicitly states 'RSA 私钥解密' (RSA private key decryption), clearly identifying the tool's operation on a specific resource. It distinguishes itself from sibling tools like rsa_encryption and rsa_sign/verify by specifying the decryption function and listing decryption-specific parameters.

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 provides key usage guidance: padding mode must match encryption, and password is needed if the private key is password-protected. However, it does not explicitly mention alternatives or when to use this tool versus other RSA operations, so it falls short of a 5.

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