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jwt-decoder

Read-onlyIdempotent

Decode a JWT into its header and payload. Does NOT verify the signature — use this for inspection only, never to trust the token's claims.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
tokenYesThe JWT to decode. Standard 3-part base64url-encoded format: header.payload.signature.

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
headerYesDecoded header JSON.
expiredYesWhether the token has expired, or null if no exp.
payloadYesDecoded payload JSON.
issued_atYesISO timestamp from 'iat' claim, or null.
expires_atYesISO timestamp from 'exp' claim, or null.
not_beforeYesISO timestamp from 'nbf' claim, or null.
signature_presentYesWhether the signature segment is non-empty.
signature_verifiedYesAlways false — this tool does not verify signatures.

Schema Changelog

Changes observed during successful MCP inspections. Dates show when Glama detected each change.

  1. First observed

TDQS

A4.5/5.0
Behavior5/5

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false. The description adds the critical behavioral fact that the tool does NOT verify the signature, which is beyond the annotations and essential for safe use. This fully discloses the tool's limitations.

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 with no fluff. It leads with the core action, then adds the critical caveat. Every word earns its place.

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

Completeness5/5

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

For a simple tool with one parameter and an output schema, the description covers the purpose, the key non-verification behavior, and usage caution. There is no need to explain return values since the output schema exists. The description is complete for safe and correct usage.

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 100%, and the parameter 'token' has a clear description including the expected format. The tool description does not add any additional parameter semantics beyond what the schema already documents, so the baseline of 3 is appropriate.

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 opens with a specific verb and resource: 'Decode a JWT into its header and payload.' This clearly states what the tool does and distinguishes it from any potential verifier or other JWT-related tool. The mention of 'header and payload' makes the output explicit.

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 explicitly states 'use this for inspection only' and warns 'never to trust the token's claims,' providing clear when-to-use and when-not-to-use guidance. However, it does not name any alternative tool for signature verification, so it falls slightly short of the highest bar for explicit alternatives.

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

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TDQS

A3.9/5.0
Disambiguation4/5

Most tools have distinct purposes. However, 'hex-to-rgb' is redundant with 'color-converter', which already handles hex-to-RGB conversion, causing potential confusion.

Naming Consistency4/5

Names follow a consistent lowercase-with-hyphens style, but vary in pattern (e.g., 'angle-converter', 'average-calculator', 'dedup-lines'). One tool ('internal-do-not-call') deviates from the descriptive norm.

Tool Count2/5

With 46 tools, the server is heavily populated. Many converters could be merged into a generic unit converter, and there is redundancy, making the surface unnecessarily large for a single server.

Completeness4/5

The server covers a broad range of utility domains: converters, text processing, math, cryptography, etc. Minor redundancies exist (e.g., hex-to-rgb vs color-converter), but the set is otherwise comprehensive.

Resources