OnlineCyberTools MCP (280+ filterable tools)

crypto_blake2

Read-onlyIdempotent

Compute a BLAKE2b or BLAKE2s digest of a string, with optional keyed MAC mode and choice of eight output lengths.

Instructions

BLAKE2 Hash Generator. Compute a BLAKE2b or BLAKE2s digest of a text string, with an optional keyed (HMAC-style) mode and a choice of eight output lengths (BLAKE2b-512/384/256/160, BLAKE2s-256/224/160/128). Use crypto_blake3 for the faster XOF-capable successor, crypto_hash for MD5/SHA-1/SHA-256/SHA-512, crypto_sha3 for SHA-3/Keccak, crypto_whirlpool for Whirlpool, or crypto_ripemd for RIPEMD; reach for BLAKE2 when you want an RFC 7693 digest faster than SHA-2 at SHA-3-level security, or a keyed MAC (used by Zcash, Nano, argon2). Runs locally on the input you provide: read-only, non-destructive, deterministic (keyed mode is deterministic too), contacts no external service, and is rate-limited (5 requests/minute for anonymous callers). Returns the digest as lowercase hex plus uppercase hex, with the resolved variant, algorithm, encoding, byte length, bit count, and keyed flag.

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": {
      "text": "<text>"
    },
    "name": "crypto_blake2"
  }
}

Input Schema

Name	Required	Description	Default
`text`	Yes	Data to hash, interpreted per the encoding field. The empty string is valid.
`encoding`	No	How to decode text into bytes before hashing: UTF-8 text (default), hex, or base64. Invalid hex/base64 is rejected.	text
`variant`	No	BLAKE2 variant and digest size. blake2b* is 64-bit-optimized (up to 512-bit); blake2s* is 8-to-32-bit-optimized (up to 256-bit). Defaults to blake2b512.	blake2b512
`key`	No	Optional UTF-8 key. When non-empty, a keyed (MAC) digest is produced and the keyed flag becomes true; when omitted or empty, a plain unkeyed digest is returned.

Output Schema

Name	Required	Description
`hash`	No	Digest as lowercase hex.
`algorithm`	No	Resolved variant id, e.g. blake2b512.
`variant`	No	Human-readable variant name, e.g. BLAKE2b-512.
`length`	No	Digest length in bytes.
`bits`	No	Digest length in bits (length x 8).
`encoding`	No	Resolved input encoding applied to text (text, hex, or base64).
`keyed`	No	True when a non-empty key was supplied (keyed/MAC digest).
`uppercase`	No	The same digest in uppercase hex.

Schema Changelog

Changes observed during successful MCP inspections.

Changed13 schema fields changedv0.5.1Jun 3, 2026

addedInput schema / additionalProperties
```
Added value: +false
```
addedInput schema / properties / encoding / default
```
Added value: +"text"
```

addedInput schema / properties / encoding / description

Added value: +"How to decode text into bytes before hashing: UTF-8 text (default), hex, or base64. Invalid hex/base64 is rejected."

addedInput schema / properties / encoding / enum

Added value: +[
+  "text",
+  "hex",
+  "base64"
+]

addedInput schema / properties / key / description

Added value: +"Optional UTF-8 key. When non-empty, a keyed (MAC) digest is produced and the keyed flag becomes true; when omitted or empty, a plain unkeyed digest is returned."

removedInput schema / properties / key / nullable
```
Removed value: -true
```
addedInput schema / properties / key / type
```
Added value: +"string"
```

addedInput schema / properties / text / description

Added value: +"Data to hash, interpreted per the encoding field. The empty string is valid."

addedInput schema / properties / variant / default
```
Added value: +"blake2b512"
```

addedInput schema / properties / variant / description

Added value: +"BLAKE2 variant and digest size. blake2b* is 64-bit-optimized (up to 512-bit); blake2s* is 8-to-32-bit-optimized (up to 256-bit). Defaults to blake2b512."

addedInput schema / properties / variant / enum

Added value: +[
+  "blake2b512",
+  "blake2b384",
+  "blake2b256",
+  "blake2b160",
+  "blake2s256",
+  "blake2s224",
+  "blake2s160",
+  "blake2s128"
+]

changedInput schema / required

Previous value: -[
-  "text",
-  "encoding",
-  "variant",
-  "key"
-]New value: +[
+  "text"
+]

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "algorithm": {
+      "description": "Resolved variant id, e.g. blake2b512.",
+      "type": "string"
+    },
+    "bits": {
+      "description": "Digest length in bits (length x 8).",
+      "type": "integer"
+    },
+    "encoding": {
+      "description": "Resolved input encoding applied to text (text, hex, or base64).",
+      "type": "string"
+    },
+    "hash": {
+      "description": "Digest as lowercase hex.",
+      "type": "string"
+    },
+    "keyed": {
+      "description": "True when a non-empty key was supplied (keyed/MAC digest).",
+      "type": "boolean"
+    },
+    "length": {
+      "description": "Digest length in bytes.",
+      "type": "integer"
+    },
+    "uppercase": {
+      "description": "The same digest in uppercase hex.",
+      "type": "string"
+    },
+    "variant": {
+      "description": "Human-readable variant name, e.g. BLAKE2b-512.",
+      "type": "string"
+    }
+  },
+  "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 declare readOnlyHint=true, destructiveHint=false, idempotentHint=true. The description adds useful context: runs locally, deterministic, rate-limited (5 req/min for anonymous), contact no external service, and details output fields.

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 long but well-structured, front-loading purpose and usage, then behavioral details, then output. Every sentence adds information, though slightly verbose for a concise tool.

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?

Output schema exists, and the description details the return fields (digest formats, variant, algorithm, encoding, byte length, bit count, keyed flag). No gaps for this hash tool.

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

Parameters5/5

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

Despite 100% schema coverage, the description adds significant value: explains variant optimization (64-bit vs 8-32-bit), encoding interpretation, keyed mode behavior, and return metadata (lowercase/uppercase hex, flags).

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 computes BLAKE2b or BLAKE2s digests of a text string, with explicit variant options and keyed mode. It distinguishes from siblings like crypto_blake3, crypto_hash, etc.

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 provides when to use (e.g., 'when you want an RFC 7693 digest faster than SHA-2 at SHA-3-level security') and directs to alternatives for other needs (crypto_blake3 for XOF, crypto_hash for MD5/SHA, etc.).

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

Deploy Server