prometeu-studio/docs/pbs/agendas/17.3. Compatibility Workshop 3 - Compatibility Matrices and Published Claims.md

PBS Compatibility Workshop 3

Status: Active

Purpose

Run the third focused discussion for 17. Compatibility and Evolution Policy.md on support claims over time:

• compatibility matrices,
• supported combinations,
• published claims,
• and how those claims age or retire.

Why This Slice Third

This slice follows domain and lifecycle policy because matrix policy is where those choices become operational.

Proposed Meeting Order

1. Reconfirm domain and lifecycle decisions from Workshops 1 and 2.
2. Close the shape of the compatibility matrix.
3. Close what counts as a published support claim.
4. Close how claims retire or narrow over time.
5. Record artifact-specific leftovers for Workshop 4.

Decisions To Produce

1. The compatibility-matrix dimensions PBS must publish.
2. The policy for published support claims.
3. The relationship between claims, conformance, and regression.
4. The retirement policy for supported combinations.

Candidate Decisions

1. Publish A Matrix Across The Major Compatibility Domains

Candidate direction:

• the matrix should cover at least: language line, stdlib line, runtime line, and conformance claim level.

Rationale:

• These are the main axes users will rely on.

2. Published Claims Must Be Backed By Conformance Or Regression Evidence

Candidate direction:

• support claims are not just prose;
• they must correspond to maintained test evidence where support is promised.

Rationale:

• This aligns policy with 13.

3. Unsupported Combinations Must Be Explicit

Candidate direction:

• the matrix must allow explicit “unsupported” states rather than implying silence equals support.

Rationale:

• This reduces accidental ambiguity.

Questions To Resolve In The Room

1. What exact axes belong in the official matrix?
2. Must every supported combination have conformance evidence?
3. How should experimental or provisional combinations be labeled?
4. When support is dropped, how is that reflected in the matrix and docs?
5. Which parts of this are policy versus test-harness detail?

Expected Outputs

1. a decision record for the compatibility-matrix model,
2. a published-claims policy note,
3. and alignment tasks for 13.

Explicit Deferrals For Workshop 4

• PBX compatibility,
• binary-loading policy,
• and artifact-line changes.

Inputs

• docs/pbs/specs/13. Conformance Test Specification.md
• docs/pbs/specs/17. Compatibility and Evolution Policy.md
• docs/pbs/agendas/13.4. Conformance Workshop 4 - Regression and Compatibility Matrices.md
• docs/pbs/agendas/17.1. Compatibility Workshop 1 - Compatibility Domains and Promise Levels.md
• docs/pbs/agendas/17.2. Compatibility Workshop 2 - Deprecation, Removal, and Migration Duties.md