io.github.daedalus/mcp-cryptography

by daedalus

Overview Schema Source Related Servers Discussions Admin

Python

Remote

generate_symmetric_key

Generate a base64-encoded 32-byte symmetric key for Fernet encryption.

Instructions

Generate a Fernet symmetric key.

Returns: Base64-encoded 32-byte key suitable for Fernet encryption.

Example: >>> key = generate_symmetric_key() >>> len(key) # 44 characters base64 encoded 44

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "generate_symmetric_key"
  }
}

Input Schema

Name	Required	Description	Default
No arguments

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.1Jul 30, 2026

TDQS

A4.2/5.0

Behavior4/5

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

Discloses the output type and length, includes an example illustrating typical usage. No annotations exist, so description compensates well by clarifying the return value and the 32-byte key size.

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?

Highly concise with a front-loaded purpose statement followed by a clear description of the return format and a helpful example. Every sentence is meaningful and efficient.

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?

For a zero-parameter tool with an output schema, the description provides necessary detail (purpose, output format, example). Could add a note on usage context (e.g., for symmetric encryption), but overall complete.

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?

No parameters; input schema coverage is 100%. Description adds value with an example showing how to call the function and confirming the output length, exceeding the baseline of 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?

Clearly states it generates a Fernet symmetric key and specifies the output format (Base64-encoded 32-byte key). Distinguishes from sibling tools like generate_rsa_key and generate_x25519_key by naming the algorithm.

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

Usage Guidelines3/5

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

Implies usage for symmetric key generation but lacks explicit guidance on when to use this tool versus alternatives like generate_rsa_key or generate_random_bytes. No when-not or context provided.

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