qCompute — Environment Transition Engine

File: qc_Transitions.md
Layer: RTT‑Inside Compute Harness
Status: Canonical (2026)

The Transition Engine governs movement between qCompute environments:

sandbox → production → archive

Transitions are deterministic, token‑gated, and replay‑verifiable.

qCompute computes structure, not amplitudes.

1. Purpose#

The Transition Engine:

• validates environment transitions
• enforces token requirements
• closes the current frame
• opens a new frame
• updates drift bounds
• updates backend legality
• updates lineage
• emits transition metadata for capture
• verifies transitions during replay

Transitions are structural governance events.

2. Environments#

qCompute defines three environments:

3. Legal Transitions#

Only two transitions are legal:

sandbox → production
production → archive

All other transitions are illegal:

sandbox → archive      (forbidden)
production → sandbox   (forbidden)
archive → anything     (forbidden)

If illegal:

allowed: false
reason: "illegal transition"

4. Token Requirements#

Transitions require tokens:

If token missing:

allowed: false
reason: "token required"

5. Transition Effects#

A transition performs:

1. close current frame
2. update environment
3. reset drift
4. recompute backend legality
5. open new frame
6. append lineage entry
7. emit transition metadata

Transitions always open a new frame.

6. Transition Metadata (Capture)#

Each transition produces:

transition:
  from: "<env>"
  to: "<env>"
  token_used: "<token-id>"
  timestamp: "<iso8601>"
  hash_prev: "<sha256>"
  hash_self: "<sha256>"

All fields are required.

7. Routing Interaction#

Router treats transitions as strongest‑priority triggers:

• always opens new frame
• always resets drift
• always rechecks backend legality
• always updates environment

Routing reason:

"environment-transition"

8. Drift Interaction#

Transitions reset drift:

drift_total = 0

New drift bound is determined by the new environment:

9. Backend Interaction#

After transition:

• backend legality is rechecked
• r3 becomes legal only in production
• all backends become illegal in archive

If backend becomes illegal:

• frame closes
• new frame opens with legal backend

10. Replay Verification#

Replay reconstructs transitions by:

1. reading transition entries
2. verifying legality
3. verifying token usage
4. verifying environment sequence
5. verifying frame boundaries
6. verifying drift resets
7. verifying backend legality
8. verifying hash chain integrity

Replay must confirm:

• transitions match canonical rules
• no illegal transitions occur
• archive is terminal

Replay is deterministic and read‑only.

11. Invariants#

1. only sandbox → production → archive is legal
2. transitions require tokens
3. transitions always open new frames
4. transitions reset drift
5. transitions update backend legality
6. transitions update environment
7. archive forbids all operators
8. archive is terminal
9. hash chain must remain valid

12. Summary#

The Transition Engine provides:

• deterministic environment changes
• token‑gated governance
• drift resets
• backend legality enforcement
• frame segmentation
• replay‑verifiable lineage

Transitions are the governance backbone of qCompute.