add-tsl-extension

name	add-tsl-extension
description	Add a target extension or machine-profile family through TSL source data, typed compiler capabilities, generated artifacts, verification, and tests. Use when asked to add a SIMD ISA or extension, fixed or scalable profile, compiler-vector overlay, target family, machine profile, feature or compile mode, or the first primitive slice for a new target.

Add TSL Extension

Workflow

1. Read AGENTS.md, CHARTER.md, PLANS.md, tsldata/AGENTS.md, tslc/AGENTS.md, tslc/CHARTER.md, and docs/add-extension.md completely. Inspect the closest extension family, target family, and machine profiles.
2. Define the target contract before editing: extension/family names, vector width model, inheritance/superseding, supported backends, feature and compile modes, profile selection, target triples/flags, headers/modules, and runner.
3. Add source-owned routing and capabilities in tsldata/detail/target_families.tsl, extension metadata in tsldata/extensions/extension.tsl, and machine instances in supplementary/buildsystem/machine_profiles.json. Do not branch on the new name in generic compiler stages.
4. Add typed catalog/schema/backend support only for concepts the current model cannot express. Keep selection and lowering driven by source capabilities; keep target syntax and intrinsic composition backend-owned.
5. Prove one small primitive/type slice through selection, lowering, rendering, generated build, and value tests before broadening coverage. Use the primitive or primitive-implementation skill for that slice when applicable.
6. If the target needs a new compiler, cross-target path, runner, emulator, or preflight behavior, also use extend-tslc-verification. Keep tool paths injectable and unavailable hardware/toolchains skip-safe.
7. Test catalog promotion, capability validation, profile selection, lowering, backend spelling, verifier configuration, and deterministic diagnostics.
8. Run a focused smoke generation, inspect emitted target facts, then broaden to the full Python suite and generated gates justified by the slice.

Checks

• The next similar extension should mostly add source data, profiles, implementations, and tests rather than new name classifiers.
• Unsupported backend/profile/type combinations must remain explicit.
• Templates must format typed decisions, not infer target semantics.
• Update coverage ratchets only after generated build/value behavior is stable and the task explicitly authorizes baseline changes.

Useful Commands

python -m compileall -q tslc/src/tslc
PYTHONPATH=tslc/src python -m pytest -q tslc/tests/test_catalog.py tslc/tests/test_catalog_validation.py
PYTHONPATH=tslc/src python -m pytest -q tslc/tests/test_backend_target_capability.py tslc/tests/test_profile_rendering.py
PYTHONPATH=tslc/src python -m pytest -q tslc/tests/test_select_and_lower*.py tslc/tests/test_build_verify_config.py
PYTHONPATH=tslc/src python -m pytest -q tslc/tests