OnlineCyberTools MCP (280+ filterable tools)

math_random_number_generator

Read-only

Generate cryptographically secure random integers, floats, booleans, UUIDs, hex strings, or base64 bytes using CSPRNG with rejection sampling for unbiased results.

Instructions

Generate Cryptographically Secure Random Values. Generates uniform random integers, floats, booleans, UUIDs (v4/v7), hex strings, or base64-encoded bytes using crypto.getRandomValues (CSPRNG), with rejection sampling to eliminate modulo bias. Pick the value family with operation. Use this for one numeric or token-style value family per call; for fake structured records (names, emails, CSV/JSON rows) use data_random_data_generator instead. An optional seed switches to a deterministic xoshiro128** PRNG for reproducible output — never use seeded output for keys, salts, tokens, nonces, or IVs. Read-only, non-destructive, no auth; rate-limited to 60 requests/minute per client. Returns the generated values as an array.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`operation`	Yes	Value family to generate. Determines which other fields are required.
`min`	No	Lower bound (required for integer/float; must be strictly less than max). Integers must be whole numbers.
`max`	No	Upper bound (required for integer/float; must be strictly greater than min).
`count`	No	How many values to generate (integer/float/boolean/uuid/hex/bytes).
`inclusive`	No	Whether max is included in the range. Integer default true; float default false. Ignored by other operations.
`version`	No	UUID layout, used only when operation is uuid. v4 is fully random; v7 is timestamp-ordered (RFC 9562).	v4
`length`	No	Output length per value — hex character count, or raw byte count for bytes (base64 is longer). Required for hex/bytes.
`seed`	No	Optional seed string for deterministic xoshiro128** output (reproducible, NOT cryptographically secure). Omit for CSPRNG. Max 1024 characters.

Output Schema

TableJSON Schema

Name	Required	Description
`success`	No	True when generation succeeded.
`operation`	No	The operation that was executed (echoed from the request).
`count`	No	Number of values returned (length of values).
`values`	No	Generated values: numbers for integer/float, booleans for boolean, or strings for uuid/hex/bytes (base64).
`error`	No	Present only on failure (HTTP 400) with the validation message; omitted on success.

Schema Changelog

Changes observed during successful MCP inspections.

Changed17 schema fields changedv0.5.1Jun 3, 2026

addedInput schema / additionalProperties
```
Added value: +false
```
addedInput schema / properties / count / default
```
Added value: +1
```

addedInput schema / properties / count / description

Added value: +"How many values to generate (integer/float/boolean/uuid/hex/bytes)."

addedInput schema / properties / count / maximum
```
Added value: +1000
```
addedInput schema / properties / count / minimum
```
Added value: +1
```

addedInput schema / properties / inclusive / description

Added value: +"Whether max is included in the range. Integer default true; float default false. Ignored by other operations."

addedInput schema / properties / length

Added value: +{
+  "description": "Output length per value — hex character count, or raw byte count for bytes (base64 is longer). Required for hex/bytes.",
+  "maximum": 1024,
+  "minimum": 1,
+  "type": "integer"
+}

addedInput schema / properties / max / description

Added value: +"Upper bound (required for integer/float; must be strictly greater than min)."

changedInput schema / properties / max / type

Previous value: -"integer"New value: +"number"

addedInput schema / properties / min / description

Added value: +"Lower bound (required for integer/float; must be strictly less than max). Integers must be whole numbers."

changedInput schema / properties / min / type

Previous value: -"integer"New value: +"number"

addedInput schema / properties / operation / description

Added value: +"Value family to generate. Determines which other fields are required."

addedInput schema / properties / operation / enum

Added value: +[
+  "integer",
+  "float",
+  "boolean",
+  "uuid",
+  "hex",
+  "bytes"
+]

addedInput schema / properties / seed

Added value: +{
+  "description": "Optional seed string for deterministic xoshiro128** output (reproducible, NOT cryptographically secure). Omit for CSPRNG. Max 1024 characters.",
+  "maxLength": 1024,
+  "type": "string"
+}

addedInput schema / properties / version

Added value: +{
+  "default": "v4",
+  "description": "UUID layout, used only when operation is uuid. v4 is fully random; v7 is timestamp-ordered (RFC 9562).",
+  "enum": [
+    "v4",
+    "v7"
+  ],
+  "type": "string"
+}

changedInput schema / required

Previous value: -[
-  "operation",
-  "min",
-  "max",
-  "count",
-  "inclusive"
-]New value: +[
+  "operation"
+]

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "count": {
+      "description": "Number of values returned (length of values).",
+      "type": "integer"
+    },
+    "error": {
+      "description": "Present only on failure (HTTP 400) with the validation message; omitted on success.",
+      "type": "string"
+    },
+    "operation": {
+      "description": "The operation that was executed (echoed from the request).",
+      "type": "string"
+    },
+    "success": {
+      "description": "True when generation succeeded.",
+      "type": "boolean"
+    },
+    "values": {
+      "description": "Generated values: numbers for integer/float, booleans for boolean, or strings for uuid/hex/bytes (base64).",
+      "items": {
+        "type": "string"
+      },
+      "type": "array"
+    }
+  },
+  "type": "object"
+}

First observedv0.1.0May 31, 2026

TDQS

A4.7/5.0

Behavior4/5

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

Annotations already indicate readOnlyHint=true and destructiveHint=false. Description adds that it uses crypto.getRandomValues (CSPRNG) with rejection sampling for bias elimination, optional deterministic PRNG with seed, and rate limiting (60 req/min). No contradictions.

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?

Description is concise (3-4 sentences), front-loaded with main purpose, and every sentence adds value. No redundant information.

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?

Given the tool's complexity (8 parameters, output schema exists), the description covers purpose, sibling differentiation, behavioral details, parameter relationships, and return format. Output schema exists but description mentions 'returns generated values as an array', which is sufficient.

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?

Schema description coverage is 100%, so baseline is 3. Description adds context beyond schema: explains that operation determines which fields are required, and warns that seeded output is not cryptographically secure. Provides meaningful guidance not in 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 clearly states the tool generates cryptographically secure random values and lists specific value families (integers, floats, booleans, UUIDs, hex, bytes). It distinguishes itself from data_random_data_generator for structured records, providing a specific verb and resource.

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?

Explicitly states when to use (one numeric/token-style family per call) and when not to (use data_random_data_generator for structured data). Also warns against using seeded output for security-sensitive purposes. Provides clear alternative and context.

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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