# STS — STATE & TRANSITION SPEC
version: v1.0
status: ACTIVE
parent: master_architecture_index.md
phase: 02
phase_name: Architecture & Engineering Canon
document_role: state_and_transition_standard_for_phase_02

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## 1. OBJECTIVE

Define canonical state logic for governed Devon flows.

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## 2. STATE PRINCIPLE

A state exists only if:
- it is named
- it is observable
- it has allowed transitions
- it has entry and exit conditions

No hidden state allowed.

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## 3. MINIMUM CANONICAL STATES

- initialized
- context_resolved
- interpreted
- normalized
- policy_checked
- validated
- execution_ready
- executed
- audited
- promoted
- failed
- missing

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## 4. TRANSITION PRINCIPLE

A transition is valid only if:
- origin state is valid
- destination state is valid
- transition trigger exists
- policy allows it
- evidence supports it where required

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## 5. BLOCKING RULE

Transition must stop when:
- required evidence is missing
- policy check fails
- validation fails
- execution precondition fails

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## 6. FAILURE RULE

Failure must resolve to:
- FAIL when evidence exists and validation fails
- MISSING when evidence does not exist

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## 7. ACCEPTANCE CRITERIA

STS is valid only if:
- states are explicit
- transitions are explicit
- blocking rules are explicit
- failure model matches global canon