ncloud-gov-mcp-server

ncloud_kms_decrypt

Read-only

Decrypt KMS-encrypted ciphertext using AES256 or RSA2048 keys. Pass keyTag and ciphertext with ncpkms prefix to obtain plaintext.

Instructions

Decrypt ciphertext using a KMS key. Only AES256 or RSA2048 key types supported. Ciphertext must include KMS prefix (ncpkms:version:ciphertext).

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "keyTag": "<keyTag>",
      "ciphertext": "<ciphertext>"
    },
    "name": "ncloud_kms_decrypt"
  }
}

Input Schema

Name	Required	Description
`keyTag`	Yes	Key tag - unique identifier derived from key name
`context`	No	Base64-encoded context used during encryption (required if convergent encryption was used)
`ciphertext`	Yes	Ciphertext data including KMS prefix (string or array of strings)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.1Aug 2, 2026

TDQS

A4.4/5.0

Behavior4/5

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

The readOnlyHint annotation already indicates a non-destructive read operation. The description adds valuable behavioral context by specifying the supported key algorithms and the mandatory KMS prefix, which are not disclosed in annotations. No contradictions exist.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences, front-loaded with the action, and contains no filler. Every sentence provides operational constraints that are useful for correct invocation. Excellent conciseness.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers the essential invocation details: supported key types, ciphertext prefix requirement. It does not explicitly state the return value, but the output (decrypted plaintext) is implied by 'decrypt'. Since no output schema exists, a brief note on return format would improve completeness, but the core usage is sufficiently covered.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema provides 100% parameter descriptions, so the baseline is 3. The description adds extra meaning by highlighting key type restrictions relevant to keyTag and reiterating the ciphertext prefix format, which reinforces the schema's ciphertext description. This modest addition warrants a 4.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action: 'Decrypt ciphertext using a KMS key.' It also specifies supported key types (AES256 or RSA2048) and the required ciphertext prefix format, distinguishing this tool from sibling KMS operations like encrypt, sign, or verify.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear usage context by stating which key types are supported and the required ciphertext format, giving the agent enough information to decide when this tool is appropriate. It does not explicitly exclude alternatives, but the constraints effectively guide selection.

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

Deploy Server