ZapifyAPI MCP Server

decode_jwt

Decode JWT tokens to inspect header and payload without signature verification. Useful for debugging and understanding token contents.

Instructions

Decode a JWT token (header + payload) without verification.

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": {
      "token": "<token>"
    },
    "name": "decode_jwt"
  }
}

Input Schema

Name	Required	Description	Default
`token`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Aug 3, 2026

TDQS

A3.8/5.0

Behavior3/5

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

With no annotations, the description carries the burden of safety disclosure. It does disclose the key behavioral trait of not verifying signatures, which is a critical security caveat. However, it does not mention error handling, malformed tokens, or what exactly is returned (e.g., JSON object vs. separate fields), leaving some gaps.

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?

A single, direct sentence with no unnecessary words. The information is front-loaded and every word adds value, making it highly concise and well-structured.

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 simple utility with one parameter and no output schema, the description covers the core function and the key limitation (no verification). It does not detail return format or error behavior, but given the tool's simplicity and clarity, it is nearly complete.

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

Parameters3/5

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

Schema coverage is 0%, so the description must compensate. It identifies the parameter as a 'JWT token', which gives semantic meaning to the otherwise bare 'string' type. But it does not elaborate on token format (e.g., three dot-separated parts) or how the token should be provided, so compensation is partial.

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 uses the specific verb 'decode' with the resource 'JWT token' and explicitly states the scope ('header + payload') and an important distinction ('without verification'). This clearly distinguishes it from any potential verification tool and aligns with the tool's function.

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?

The phrase 'without verification' implies this tool is for inspection only, not for validating tokens, giving some context on when to use it. However, it does not explicitly state use cases or alternatives, so guidance is implied rather than explicit.

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