Tractum — the signature now covers the evidence.

In July I shipped Claudeway: multi-agent consensus with cryptographic receipts, post-quantum signing from day one, one live receipt on four Nostr relays. Today v0.5.0 lands under a new name — tractum — and ships the thing the name was always pointing at: the signed chain from evidence to decision. pip install tractum. The site is tractum.dev.

The name

Claudeway was always the wrong name. It said Claude; the layer underneath isn’t Claude-specific and never was — the MCP server reaches any MCP-aware agent, and the adapters wrap CrewAI, LangGraph, and Microsoft Agent Framework. A consensus primitive named after one model vendor dates itself the day someone runs it against something else.

Tractum is Latin: “a drawing together” — the root of contract and treaty. That is the product. Agents drawn together into one signed agreement.

The rename economics worked out because of a decision made in July: the last claudeway release to PyPI was v0.4.0, and it stays there frozen — a tombstone pointing at the new name rather than an abandoned package. Tractum took a fresh slot and shipped straight to v0.5.0, so the version number never went backwards even though the name did. pip install tractum just works, first try.

One deliberate fossil: the wire-format type tags are unchanged. Receipts still carry claudeway.consensus.v1/v2, claudeway.agent-statement.v1, and the claudeway.receipt.v1 envelope, and the verifier accepts them forever. Receipts published in July still verify under v0.5.0. Artifacts don’t get rewritten because branding did.

Decision + evidence, one signature

The gap the July release left open: a receipt attested the answer, but not the transcripts it was computed from. A quorum receipt without its evidence is a verdict with no case file.

v0.5.0 ships .curt linkage and closes it:

  • build_curt_transcript renders a consensus result as a conforming .curt v1 document, with per-message agent provenance via the agent-context extension
  • link_receipt embeds the transcript refs — {id, sha256} — inside the signed payload, so the aggregate signature covers the linkage itself; you can’t swap the evidence under a valid receipt
  • emit_curt_decision emits receipt + evidence as one .curt artifact (the consensus-receipt extension)
  • verify_curt_link verifies the whole chain through the existing crypto paths — operator key, per-agent keys, quorum, and now the hash binding

Unlinked payloads stay byte-identical to the 0.4.0 wire format. Linkage is additive or nothing.

The bug worth quoting from the build: .curt message ids used only the first 12 characters of the content-addressed conversation id. Two transcripts whose ids shared leading digest characters — about 1 in 256 — collided when merged into a decision artifact, and emit_curt_decision silently dropped the evidence. A signed receipt pointing at evidence that quietly isn’t there is worse than no receipt at all: it’s a verdict with the case file missing and no one the wiser. Ids now embed the full conversation id, with a regression test. The suite is 197 tests.

The MCP server can’t pretend

The MCP server got hardened in three directions, all the same instinct — the tool must never produce something less than it appears:

  • reach_consensus always signs. No configured operator key? It signs with a fresh ephemeral keypair and tells you so — the public key rides in the response, metadata.operator_key: "ephemeral" marks the mode. v0.4.x returned an unsigned receipt that verify_consensus would then reject. Dead end removed.
  • TRACTUM_REQUIRE_PINNED_KEY=1 for deployments that must never ship an ephemeral-signed receipt: without a configured signing key, the call fails loudly instead of signing with a throwaway key.
  • Dry-run mode (TRACTUM_MCP_DRY_RUN=1, or "dry_run": true per call) runs deterministic offline stub agents — real per-agent keypairs, real statement signatures, zero API calls — and the receipt self-identifies as a dry run so it can never pass for a live decision.

What shipped

v0.5.0 on PyPI as tractum: the rename, .curt linkage, MCP signing + dry-run hardening. 197 tests green. The docs moved to jordannewell.github.io/tractum, the MCP demo is a five-minute path (docs/mcp-demo.md), and the live relay receipt from July still verifies — different name, same signatures.

The thesis hasn’t moved since July: agent coordination records are long-lived artifacts, EU AI Act enforcement is live, and provenance is either born signed or it’s hearsay. What changed is that the chain is complete. Signed evidence (.curt) → signed agreement (quorum receipt) → one artifact an auditor can verify end to end.

The rule

A receipt without its evidence is a verdict without a transcript.

Decisions that matter need both, born signed, in one artifact. That’s the whole product.

Filed under /projects and /ai. Product page: Tractum. Source: github.com/JordanNewell/tractum. Site: tractum.dev. Previous: Shipping Claudeway.