Burs-IA Utils

Derivar clave con PBKDF2

kdf-pbkdf2

Read-onlyIdempotent

Deriva una clave con PBKDF2 (RFC 8018). Iteraciones máx. 50.000. Cuándo: hay que derivar una clave a partir de una contraseña o un secreto con parámetros conocidos. No para: derivar material de clave con HKDF (kdf-hkdf). Efectos secundarios: ninguno (solo lectura, sin red, sin estado guardado). Determinista: la misma entrada da la misma salida. Límites: entrada JSON de hasta 64 KB, 1 s por llamada, resultado de hasta 1 MB.

EN: Derives a key with PBKDF2 (RFC 8018) using HMAC-SHA256/SHA512/SHA1. Iterations capped at 50,000 and output at 128 bytes to keep calls fast. When: a key has to be derived from a password or secret with known parameters. Not for: deriving key material with HKDF (kdf-hkdf). Side effects: none (read-only, no network access, no stored state). Deterministic: the same input gives the same output. Limits: JSON input up to 64 KB, 1 s per call, result up to 1 MB.

Input Schema

Name	Required	Description	Default
`salt`	Yes	Salt (string; required; up to 1024 chars).
`digest`	No	PRF hash (optional; one of: sha256, sha512, sha1; default "sha256").	sha256
`length`	No	Derived key length in bytes (integer; optional; default 32; min 1; max 128).
`password`	Yes	Password or secret (string; required; up to 1024 chars).
`iterations`	Yes	Iteration count (integer; required; min 1; max 50000).
`salt_encoding`	No	Encoding of salt (optional; one of: utf8, hex, base64; default "utf8").	utf8
`output_encoding`	No	Output encoding of the digest (optional; one of: hex, base64, base64url; default "hex").	hex

Output Schema

Name	Required	Description	Default
`key`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedNov 2, 2026
- addedInput schema / properties / iterations / examples
```
Added value: +[
+  1
+]
```
- addedInput schema / properties / password / examples
```
Added value: +[
+  "password"
+]
```
- addedInput schema / properties / salt / examples
```
Added value: +[
+  "salt"
+]
```
First observedNov 1, 2026

TDQS

A4.6/5.0

Behavior5/5

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

Annotations already declare read-only, idempotent, non-destructive, and closed-world behavior. The description adds meaningful context beyond that: deterministic output, no network or stored state, iteration and output caps, and request/result size limits. There is 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 well structured and front-loaded: it states the operation, when to use it, when not to use it, side effects, determinism, and limits. It loses a point because the Spanish and English versions duplicate the same content rather than adding new 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?

The tool has an output schema, rich annotations, full parameter schema coverage, and the description adds limits, determinism, and side-effect details. An agent has everything needed to call it correctly.

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 schema already documents all seven parameters thoroughly. The description restates a few constraints such as the 50,000 iteration cap and 128-byte output cap, but it does not add per-parameter semantics beyond what the schema provides.

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 names a specific verb and resource (derive a key with PBKDF2) and includes the RFC plus supported HMAC hash variants. It explicitly distinguishes the tool from the sibling kdf-hkdf, so an agent can select it without opening schemas.

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?

It provides explicit usage guidance with a clear 'When' condition (deriving a key from a password or secret with known parameters) and a 'Not for' exclusion pointing to kdf-hkdf. This is about as clear as when-to-use guidance gets.

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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