Phase 9 Semantic Authority Recommendation¶

Recommendation¶

DecisionGraph should keep Python as the permanent semantic authority for the frozen Phase 1 scope after Phase 9.

This is a deliberate architectural choice, not a lack of confidence in the BEAM platform.

Why This Is The Right Opening Position¶

The BEAM side is already strong where the platform needed it most:

production-style event storage
supervised projection runtime
authenticated service APIs
operator console
workflow and review operations
self-hosted operational credibility

That success does not automatically answer the semantic-authority question.

The final Phase 9 evidence shows no observed frozen-core semantic drift across the current BEAM write, projection, query, and replay proof suites.

Even with that result, three issues make a handoff unnecessary or counterproductive:

1. The Remaining Cost Is Transition Cost, Not Core Correctness Cost¶

The repo now has a completed parity decision artifact in docs/benchmarks/PHASE_9_PARITY_REPORT.md. That report is good news for correctness, but it does not create enough product value to justify an authority handoff by itself.

2. Python Still Owns A Real Compatibility Surface¶

The Python package still matters for:

embedded local usage
SQLite-backed execution
offline or single-process workflows
the local CLI and semantic reference harness

If Elixir becomes authoritative, that surface needs an explicit bridge or retirement policy.

3. The BEAM Platform Has Newer Semantics Outside The Frozen Baseline¶

The BEAM platform added workflow-era behavior such as WorkflowReviewRequested. That is valid product evolution, but it is not part of the original frozen Python semantic baseline.

The project should avoid using newer BEAM-only extensions as evidence that the original reference core has already been replaced.

Practical Recommendation For Maintainers¶

Phase 9 should end with this operating model:

keep Python authoritative for the frozen core
use the Phase 9 parity report as the release gate for frozen-core BEAM parity
keep the Python local-library, CLI, and SQLite story as intentional product value
treat any future authority handoff as a new decision, not the default continuation of this phase

What Would Change This Recommendation¶

I would recommend BEAM authority in a future phase only after all of the following are true:

the Phase 9 parity report remains complete and diff-classified
no non-negotiable semantic drift remains
the Python consumer transition policy is written
rollback and governance are explicit
maintainers can explain the user benefit of the handoff, not just the implementation neatness

Why Keeping Python Authoritative Is The Final Phase 9 Outcome¶

Keeping Python as the permanent oracle is the right successful outcome because:

BEAM already delivers the runtime and product value users need
Python continues to serve the embedded reference and offline use cases well
an independent oracle keeps parity discipline strong
a full handoff would create migration work without meaningful product upside for the local-first strategy

That outcome does not mean BEAM fell short. It means the project now has a stable long-term split of responsibilities.