OnlineCyberTools MCP (280+ filterable tools)

conversion_decimal_hex

Read-onlyIdempotent

Convert decimal numbers to hexadecimal and back, with signed or unsigned interpretation at 8/16/32/64-bit widths and optional hex formatting. Includes a step-by-step conversion breakdown.

Instructions

Decimal And Hexadecimal Number Converter. Convert one whole number between decimal (base 10) and hexadecimal (base 16) in either direction, with unsigned or signed (two's-complement) interpretation at an 8/16/32/64-bit width and optional hex formatting (0x prefix, upper/lowercase, zero-padding). Use this when you need decimal-hex specifically with a step-by-step breakdown and fixed-width signed handling. Use conversion_binary_decimal for base-2 conversion, conversion_base_converter to convert an integer between arbitrary radixes 2-36, conversion_number_base to map a string of byte values across ASCII/binary/hex/decimal/octal, conversion_hex_ascii to turn hex into ASCII text, and conversion_bcd for binary-coded decimal. Runs locally via the shared logic runner: read-only, non-destructive, offline, no auth, default rate limit (60 requests/minute for anonymous callers). Returns the converted value plus the echoed settings and a per-step conversion breakdown.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`mode`	Yes	Conversion direction.
`input`	Yes	The number to convert. For decimal-to-hex, a whole decimal value with optional sign (e.g. "255" or "-42"). For hex-to-decimal, hex digits 0-9/A-F with an optional 0x prefix (e.g. "FF" or "0x1a"). Leading/trailing whitespace is trimmed; must not be blank.
`numberType`	No	Interpretation of the value. 'signed' enables two's-complement at the given bitWidth; 'unsigned' treats it as non-negative.	unsigned
`bitWidth`	No	Fixed width for signed (two's-complement) interpretation. Must be one of the enum values when numberType is 'signed'; ignored for unsigned.
`hexOptions`	No	Optional output formatting for decimal-to-hex (ignored for hex-to-decimal).

Output Schema

TableJSON Schema

Name	Required	Description
`success`	No	True when conversion succeeded; false on validation error.
`result`	No	The conversion result (present when success is true).
`error`	No	Error message (present when success is false).

Schema Changelog

Changes observed during successful MCP inspections.

Changed24 schema fields changedv0.5.1Jun 3, 2026

addedInput schema / additionalProperties
```
Added value: +false
```
addedInput schema / properties / bitWidth / default
```
Added value: +8
```

addedInput schema / properties / bitWidth / description

Added value: +"Fixed width for signed (two's-complement) interpretation. Must be one of the enum values when numberType is 'signed'; ignored for unsigned."

addedInput schema / properties / bitWidth / enum
```
Added value: +[
+  8,
+  16,
+  32,
+  64
+]
```
addedInput schema / properties / hexOptions / additionalProperties
```
Added value: +false
```

addedInput schema / properties / hexOptions / description

Added value: +"Optional output formatting for decimal-to-hex (ignored for hex-to-decimal)."

addedInput schema / properties / hexOptions / properties / padWidth / default
```
Added value: +4
```
addedInput schema / properties / hexOptions / properties / padWidth / description
```
Added value: +"Target length for zero-padding when padding is true."
```
addedInput schema / properties / hexOptions / properties / padding / default
```
Added value: +false
```
addedInput schema / properties / hexOptions / properties / padding / description
```
Added value: +"Left-pad the hex output with zeros to padWidth."
```
addedInput schema / properties / hexOptions / properties / prefix / default
```
Added value: +false
```
addedInput schema / properties / hexOptions / properties / prefix / description
```
Added value: +"Prepend \"0x\" to the hexadecimal output."
```
addedInput schema / properties / hexOptions / properties / uppercase / default
```
Added value: +true
```
addedInput schema / properties / hexOptions / properties / uppercase / description
```
Added value: +"Emit hex digits A-F uppercase; false emits a-f lowercase."
```

removedInput schema / properties / hexOptions / required

Removed value: -[
-  "prefix",
-  "uppercase",
-  "padding",
-  "padWidth"
-]

addedInput schema / properties / input / description

Added value: +"The number to convert. For decimal-to-hex, a whole decimal value with optional sign (e.g. \"255\" or \"-42\"). For hex-to-decimal, hex digits 0-9/A-F with an optional 0x prefix (e.g. \"FF\" or \"0x1a\"). Leading/trailing whitespace is trimmed; must not be blank."

addedInput schema / properties / input / minLength
```
Added value: +1
```
addedInput schema / properties / mode / description
```
Added value: +"Conversion direction."
```

addedInput schema / properties / mode / enum

Added value: +[
+  "decimal-to-hex",
+  "hex-to-decimal"
+]

addedInput schema / properties / numberType / default
```
Added value: +"unsigned"
```

addedInput schema / properties / numberType / description

Added value: +"Interpretation of the value. 'signed' enables two's-complement at the given bitWidth; 'unsigned' treats it as non-negative."

addedInput schema / properties / numberType / enum
```
Added value: +[
+  "unsigned",
+  "signed"
+]
```

changedInput schema / required

Previous value: -[
-  "mode",
-  "input",
-  "numberType",
-  "bitWidth",
-  "hexOptions"
-]New value: +[
+  "mode",
+  "input"
+]

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "error": {
+      "description": "Error message (present when success is false).",
+      "type": "string"
+    },
+    "result": {
+      "description": "The conversion result (present when success is true).",
+      "properties": {
+        "bitWidth": {
+          "description": "Echoed bit width used for signed interpretation.",
+          "type": "integer"
+        },
+        "conversionSteps": {
+          "description": "Ordered step-by-step breakdown of the conversion.",
+          "items": {
+            "properties": {
+              "calculation": {
+                "description": "The arithmetic for this step.",
+                "type": "string"
+              },
+              "description": {
+                "description": "What this step does.",
+                "type": "string"
+              }
+            },
+            "type": "object"
+          },
+          "type": "array"
+        },
+        "hexDigitCount": {
+          "description": "Number of hex digits parsed (hex-to-decimal only).",
+          "type": "integer"
+        },
+        "hexOptions": {
+          "description": "Echoed hex formatting options after defaults were applied.",
+          "properties": {
+            "padWidth": {
+              "description": "Zero-padding target length.",
+              "type": "integer"
+            },
+            "padding": {
+              "description": "Whether zero-padding was applied.",
+              "type": "boolean"
+            },
+            "prefix": {
+              "description": "Whether a 0x prefix was added.",
+              "type": "boolean"
+            },
+            "uppercase": {
+              "description": "Whether hex digits are uppercase.",
+              "type": "boolean"
+            }
+          },
+          "type": "object"
+        },
+        "input": {
+          "description": "The trimmed input value as supplied.",
+          "type": "string"
+        },
+        "mode": {
+          "description": "Echoed conversion direction.",
+          "type": "string"
+        },
+        "numberType": {
+          "description": "Echoed number interpretation (unsigned or signed).",
+          "type": "string"
+        },
+        "output": {
+          "description": "The converted value as a string (formatted hex, or decimal).",
+          "type": "string"
+        },
+        "rawHex": {
+          "description": "Unformatted hex digits before prefix/padding/case (decimal-to-hex only).",
+          "type": "string"
+        }
+      },
+      "type": "object"
+    },
+    "success": {
+      "description": "True when conversion succeeded; false on validation error.",
+      "type": "boolean"
+    }
+  },
+  "type": "object"
+}

First observedv0.1.0May 31, 2026

TDQS

A4.5/5.0

Behavior5/5

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

Annotations declare readOnlyHint=true, destructiveHint=false, idempotentHint=true. The description adds that the tool runs locally, is read-only, non-destructive, offline, no auth, and has a default rate limit. It also explains the return value includes a per-step breakdown. No contradiction.

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

Conciseness4/5

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

The description is a single paragraph that is information-dense and front-loads the main purpose. It could be slightly more structured, but it is concise and covers essential points without waste.

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?

With 5 parameters, nested objects, and an output schema, the description adequately covers the tool's behavior and return format. It mentions the step-by-step conversion breakdown, which adds value beyond the schema. However, the description could be more structured for complex parameters.

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 description coverage is 100%, so the baseline is 3. The description adds context about step-by-step breakdown and fixed-width handling but does not significantly enhance parameter understanding beyond the schema.

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 explicitly states the tool converts a whole number between decimal and hexadecimal in either direction, with details on signed/unsigned, bit widths, and hex formatting. It clearly distinguishes from siblings by listing alternative tools for other conversions.

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

Usage Guidelines5/5

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

The description provides explicit guidance on when to use this tool ('Use this when you need decimal-hex specifically with a step-by-step breakdown and fixed-width signed handling') and lists specific alternatives for other conversion needs.

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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