Burs-IA Utils

Verificar HMAC

hmac-verify

Read-onlyIdempotent

Recalcula un HMAC y lo compara en tiempo constante con el esperado (p. ej. firma de webhook). Cuándo: hay que firmar un mensaje, o comprobar una firma, con un secreto compartido que viene en la llamada. No para: calcular el HMAC (hmac-sha256). 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: Recomputes an HMAC over the data and compares it with an expected hex/base64 MAC in constant time, e.g. to check a webhook signature. When: a message has to be signed, or a signature checked, with a shared secret supplied in the call. Not for: computing the HMAC (hmac-sha256). 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
`key`	Yes	Secret key (string; required; up to 4096 chars).
`data`	Yes	Input data (string; required).
`expected`	Yes	Expected MAC, hex or base64 (string; required; up to 512 chars).
`algorithm`	No	Hash (optional; one of: sha256, sha512, sha1, sha384; default "sha256").	sha256
`key_encoding`	No	Encoding of `key` (optional; one of: utf8, hex, base64; default "utf8").	utf8
`input_encoding`	No	How `data` is encoded (optional; one of: utf8, hex, base64; default "utf8").	utf8

Output Schema

Name	Required	Description	Default
`valid`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedNov 2, 2026

addedInput schema / properties / data / examples

Added value: +[
+  "The quick brown fox jumps over the lazy dog"
+]

addedInput schema / properties / expected / examples

Added value: +[
+  "f7bc83f430538424b13298e6aa6fb143ef4d59a14946175997479dbc2d1a3cd8"
+]

addedInput schema / properties / key / examples
```
Added value: +[
+  "key"
+]
```

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 readOnly, idempotent, non-destructive and closed-world, but the description adds substantive context beyond them: constant-time comparison semantics, no network, no stored state, determinism, and concrete limits (64 KB input, 1 s per call, 1 MB result). This is exactly the extra behavioral detail annotations cannot convey.

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?

Front-loaded with the core action and organized under clear labels (Cuándo, No para, Efectos secundarios, Determinista, Límites). The full Spanish/English duplication doubles the length, which is redundant for a single-locale agent, but each individual sentence 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?

With an output schema present, the description needn't explain return values, and it covers everything else an agent needs: purpose, alternative, side effects, determinism, and operational limits. Nothing material is missing for correct invocation.

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% and all six parameters (including the three enums) are documented in the schema, so the baseline is 3. The description only alludes to the expected MAC being hex/base64 and the secret coming in the call, adding little 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?

States a specific verb and resource ('Recalcula un HMAC y lo compara en tiempo constante con el esperado') and explicitly distinguishes itself from the sibling hmac-sha256 by naming it as the tool for plain computation. An agent can tell exactly what this does versus the other HMAC tools.

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?

Explicit 'Cuándo' clause (signing or verifying a signature with a shared secret supplied in the call) and an explicit 'No para' clause routing to hmac-sha256. Both the use case and the exclusion are stated, leaving nothing to inference.

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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