pqc-migration-mcp

Give your AI agent the post-quantum migration facts it keeps guessing at.

Six tools over MCP: credential sizes, fragment counts, the reassembly window, the 39-family failure taxonomy, and benchmark scoring. Ask Claude "will our ML-KEM-768 handshake fit in a BLE MTU?" and it computes the answer instead of estimating one.

Why this exists

Agents are increasingly doing PQC migration work, and they are confidently wrong about exactly the things that matter: how big a credential actually is, how many fragments it becomes, and whether a safe reassembly cap exists at your concurrency. Those are arithmetic, not judgement — so hand the agent the arithmetic.

The protocol layer here is dependency-free. MCP is JSON-RPC 2.0 over line-delimited stdio, which is small enough to implement directly and keeps the install trivial.

Related MCP server: attestix

Install

pip install pqc-migration-mcp        # once published
pip install -e .                     # from a clone, today

30-second quickstart

# talk to it directly -- it is line-delimited JSON-RPC on stdio
echo '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}' | pqc-migration-mcp

Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "pqc-migration": {
      "command": "pqc-migration-mcp"
    }
  }
}

Restart Claude Desktop. The six tools appear under the connector.

Tools

Worked example — actual output

$ printf '%s\n' \
  '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"reassembly_window",
    "arguments":{"largest_legitimate_object":12000,"memory_budget":32768,"concurrency":3}}}' \
  | pqc-migration-mcp

{
  "is_empty": true,
  "ceiling": 10922,
  "recommended_cap": null,
  "max_safe_concurrency": 2,
  "explanation": "EMPTY WINDOW: floor 12,000 B > ceiling 10,922 B (short by 1,078 B).
    No capacity cap is both feasible and safe. Raise the budget to at least 36,000 B,
    reduce concurrency to at most 2, or choose a smaller credential."
}

The agent gets a verdict and the number that would fix it, so it can propose a concrete change rather than reporting a problem.

What this server will not tell you

It exposes detection. It does not expose repairs.

An agent can learn that a design fails krack_retransmission and exactly what the unrepaired design did. It cannot obtain the mechanism that closes it. That boundary is deliberate: an MCP tool returning repairs would let any user enumerate the entire closed set in an afternoon.

There is a test that calls describe_family for all 39 families plus every other tool, concatenates the responses, and fails if repair_mechanism, repaired_detail or repaired_held appears anywhere in the output.

Error semantics

Domain errors — an unknown algorithm, an unknown family — come back as a tool result with isError: true and a message naming the valid options, so the agent can correct itself. Only protocol faults become JSON-RPC errors (-32601 unknown method/tool, -32602 bad arguments, -32700 unparseable line).

A malformed line does not kill the loop; the server replies with a parse error and keeps serving.

Tests

pip install -e ".[dev]" && pytest      # 26 passed

Tests cover the protocol, every tool, the moat boundary, and the real stdio transport driven as a subprocess — including a check that stderr stays empty, since MCP clients read stdout as protocol and stray warnings confuse them.

Scope

Arithmetic, taxonomy lookup and scoring. No cryptography, no network, no telemetry. It does not inspect your implementation. A clean answer means your configuration is sound, not that your code enforces it.

Related

pqc-sizes · pqc-mfb · pqc-guard-action · pqc-dos-embedded

Closing the 39 families is what the closed core does. Relevant subject matter is covered by a filed provisional patent application. For commercial use of the full envelope, open a GitHub Discussion or an issue on this repository.

The PQC migration toolkit

Nine free tools for teams moving authenticated key exchange to post-quantum. They find and measure; they do not repair.

Start here: pqc-sizes tells you in five seconds whether your credential fragments and whether a safe cap exists. pqc-explorer does the same in a browser.

The closed core

Closing the 39 failure families — downgrade binding, retransmission-safe installation, fragmentation transcripts, roaming forward secrecy, multi-link key separation, admission control, group-key binding — is a separate proprietary codebase. Relevant subject matter is covered by a filed provisional patent application.

That split is measured, not asserted: under a replicate noise control only 4 of 32 repair mechanisms are externally distinguishable, so publishing these detectors does not disclose the repairs.

For commercial licensing, open a GitHub Discussion or an issue on any of these repos.

License

Apache-2.0. See LICENSE and CONTRIBUTING.md.