Post-Quantum Cryptography MCP Server

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pqc_hybrid_auth_open

Verify the sender's signature before decrypting an authenticated hybrid envelope, using expected sender identity and freshness checks to return trusted plaintext.

Instructions

Verify sender + decrypt: authenticated hybrid envelope. Requires expected sender identity. Signature verified before decryption.

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": {
      "envelope": "<envelope>"
    },
    "name": "pqc_hybrid_auth_open"
  }
}

Input Schema

Name	Required	Description
`envelope`	Yes	Authenticated envelope from pqc_hybrid_auth_seal
`key_store_name`	No	Name of stored hybrid key bundle
`pqc_secret_key`	No	Base64-encoded ML-KEM-768 secret key
`max_age_seconds`	No	Max envelope age in seconds for freshness check (default 86400 = 24h; must be positive). v2 envelopes have signed timestamps; v1 envelopes skip freshness regardless. Clock skew tolerance: 5 min.
`classical_secret_key`	No	Base64-encoded raw 32-byte X25519 secret key
`expected_sender_public_key`	No	Base64-encoded ML-DSA-65 public key (exactly one of this or expected_sender_fingerprint required)
`expected_sender_fingerprint`	No	SHA3-256 hex fingerprint of sender public key

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.10.0Nov 4, 2026

TDQS

B3.4/5.0

Behavior3/5

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

With no annotations, the description carries the full burden and does add real value by disclosing the security-critical ordering: signature verification happens before decryption, so a forged envelope is not decrypted. It stops short of stating what a failed verification returns (exception vs. error value), whether the envelope is consumed, or any key-store/permission requirements.

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?

Three short sentences, no filler, with the operation and its prerequisite front-loaded. The telegraphic fragment style ('Verify sender + decrypt:') is dense but readable, with only a minor cost in scannability.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There are no annotations and no output schema, and the description never says what comes back (plaintext bytes, an object, a verified flag) or how key material options (key_store_name vs. raw secret keys) relate. For a 7-parameter cryptographic entry point with a nested envelope object, that leaves meaningful gaps.

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 coverage is 100%, so all seven parameters are already documented in the schema, including the mutually exclusive sender-key/fingerprint choice and freshness semantics. The description's only added parameter meaning is the requirement of an expected sender identity, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific compound verb pair ('Verify sender + decrypt') against a specific resource ('authenticated hybrid envelope'), which implicitly separates it from the verify-only and open-only siblings. It never names those siblings, so an agent must infer that pqc_hybrid_auth_verify and pqc_hybrid_open are the alternatives rather than being told.

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

Usage Guidelines3/5

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

'Requires expected sender identity' gives a prerequisite, and 'authenticated hybrid envelope' implies the input must come from pqc_hybrid_auth_seal. There is no explicit when-to-use versus pqc_hybrid_open (unauthenticated decrypt) or pqc_hybrid_auth_verify (verify without decrypt), which is the exact routing decision an agent faces here.

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