Methodology packs

A methodology pack is a signed, versioned bundle that pins the compatible calculation methods and numeric parameters used for a set of outputs.

Why packs are used

• Atomic versioning: related calculation changes are activated together.
• Reproducibility: an analysis job freezes its pack when queued, so an in-flight result cannot change under a later configuration.
• Contractual reference: reports and agreements can cite one pack identity and version.
• Tamper evidence: the canonical pack body is hashed and signed; constituent changes invalidate verification.

Pack reference

Signed outputs identify the pack using three values:

{
  "methodology_pack_id": "miombo-core",
  "methodology_pack_version": "v2026.06",
  "methodology_pack_manifest_hash": "<sha256>"
}

The manifest hash binds the result to the exact signed pack. A tenant upgrade applies to future jobs; previously signed outputs continue to refer to the pack under which they were calculated.

Change control

Signed pack versions are immutable. Parameter or reference changes create a successor version with a chain pointer to its predecessor. Historical results are not silently recalculated.