Decrypts an AES-256-CBC encrypted message using a supplied passphrase, returning the original plaintext from iv:ciphertext input.
Decrypts a message
| Name | Required | Description | Default |
|---|---|---|---|
| encryptionKey | Yes | The key used for decryption | |
| encryptedMessage | Yes | The encrypted message (format: iv:ciphertext) |
| Name | Required | Description | Default |
|---|---|---|---|
| decryptedMessage | Yes | The decrypted message |
Changes observed during successful MCP inspections.
v0.0.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden, yet it discloses nothing about key requirements, failure modes on bad keys, or reversibility. It is silent on every behavioral trait an agent would need.
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 single three-word phrase is short but under-specified rather than concise: every word merely echoes the name, so nothing is front-loaded or earned.
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?
An output schema exists so return values need not be explained, but with no annotations and two required params, the description should still cover prerequisites or pairing with encrypt_message. It leaves those gaps open.
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 100%, including the iv:ciphertext format note, so the schema already documents both required parameters. The description adds no meaning beyond it, which is the baseline 3 case.
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?
"Decrypts a message" simply restates the tool name decrypt_message with no added specificity. It does not distinguish this tool from its sibling encrypt_message or state scope, format, or any qualifier.
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 no statement of when to use this tool, when not to, or how it relates to the sibling encrypt_message. The agent gets no routing signal at all.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.