Continuum Contract Artifact Interchange

[flyingrobots]

Migrated from Method backlog

This issue was created from a legacy filesystem backlog card. GitHub Issues are now the live work tracker; repository docs remain Method evidence.

Source backlog: docs/method/backlog/cool-ideas/PLATFORM_continuum-contract-artifact-interchange.md
Original lane: cool-ideas
Original legend: PLATFORM

Original backlog card

Continuum Contract Artifact Interchange

Status: cool idea, future protocol lane.

Depends on:

• Contract strands and counterfactuals
• external Continuum protocol publication work

Why later

Echo should prove local Wesley-compiled contract hosting before protocolizing
contract artifacts across runtimes.

Once local hosting, receipts, readings, CAS retention, and contract strands are
real, Continuum can define how sibling runtimes exchange contract-shaped
causal artifacts.

What it should look like

Continuum artifacts should be able to name:

• contract family
• schema codec, schema hash algorithm, and schema hash
• intent or observer kind
• basis and frontier
• payload codec, payload hash algorithm, and payload hash
• receipt refs as codec/hash tuples
• witness refs as codec/hash tuples
• reading refs as codec/hash tuples
• admission posture
• retained artifact codec/hash tuples

Sibling runtimes should exchange protocol-shaped causal artifacts, not runtime
internals.

Every encoded field that contributes to identity needs a canonical byte
serialization rule and stable interoperable codec/hash identifiers such as
multicodec and multihash labels. Semantic names like "schema hash" are not
enough for cross-runtime verification.

Acceptance criteria

• One Echo contract receipt exports as a Continuum-shaped artifact.
• A second runtime or verifier can inspect the artifact family identity without
  understanding Echo internals.
• Import is not treated as generic state snapshot sync; it preserves contract
  artifact identity and admission posture.
• Missing contract family or schema support is obstructed, not silent
  downgrade.

Non-goals

• Do not start before local contract hosting is real.
• Do not require proof-carrying execution.
• Do not design all network transport.
• Do not collapse contract artifacts into generic state snapshots.

[coderabbitai]

🔗 Related PRs

flyingrobots/echo#326 - Echo contract hosting roadmap [merged]
flyingrobots/echo#368 - feat(core): connect installed contract intent pipeline [merged]
flyingrobots/echo#371 - feat(core): advance v0.1 contract evidence and retention [merged]
flyingrobots/echo#380 - feat(core): expose retained evidence posture on readings [merged]
flyingrobots/echo#382 - 0024 universal LE binary codec + 0025 sessions design (design-only) [merged]

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[coderabbitai]

🔗 Related PRs

#18 - Align Continuum sibling runtime doctrine [closed]
#19 - Add cross-repo contract family registry [closed]
#20 - Rewrite README around witnessed causal history [closed]

---

📝 Issue Planner

_{Check the box below or use the @coderabbitai plan command to generate an implementation plan and prompts that you can use with your favorite coding assistant.}

• Create Plan

---

🧪 Issue enrichment is currently in open beta.

You can configure auto-planning by selecting labels in the issue_enrichment configuration.

To disable automatic issue enrichment, add the following to your .coderabbit.yaml:

issue_enrichment:
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    enabled: false

💬 Have feedback or questions? Drop into our discord!

[flyingrobots]

Refined by #76.

Contract artifact interchange should carry supported outcome posture, support tier, verification mode, guarantees, and non-guarantees where applicable. Missing contract family/schema support remains obstruction, not silent downgrade. Proof-carrying execution remains a future/high-assurance tier, not an interchange prerequisite.