git:20261006.d465449 to git:20261027.a12f448

# infrastructure/core/runtime/ - Runtime Helper Documentation

## Purpose

The `infrastructure/core/runtime/` package contains runtime helpers for environment setup, dependency checks, checkpointing, profiling, health, and retry behavior.

## Files

- `_python_env.py` - Python environment helpers, confined analysis-script paths,

and fail-closed analysis subprocess environments

- `python_binding.py` - lexical selected interpreter and installed dependency

declaration identity, with actual worker runtime observation and conservative

canonical analysis cache/resume refusal (see README for proof boundaries)

- `_packages.py` - package detection helpers

- `_directories.py` - directory helpers

- `checkpoint.py` - pipeline checkpointing

- `environment.py` - environment validation

- `env_deps.py` - dependency helpers

- `prepared_runtime.py` / `prepared_dispatch.py` - existing selected root runtime, declared requirement availability, and finite audited CLI dispatch without acquisition

- `setup_checks.py` - Stage 0 check-only orchestration and aggregate `run_environment_setup_checks` service (used by `scripts/pipeline/stage_00_setup.py`)

- `eta.py` - ETA helpers

- `function_profiler.py` - function profiling

- `health_check.py` - health checks

- `retry.py` - retry helpers

## See Also

- [`README.md`](README.md)

- [`../AGENTS.md`](../AGENTS.md)

## Checkpoint recovery

Checkpoint loading validates integer stage counters, finite nonnegative runtime

measurements, stage result shapes, and optional output digests before resume.

Malformed persisted fields produce an unavailable checkpoint instead of crashing

the pipeline. Failed serialization, digest reads, or writes leave the previous

valid checkpoint intact. New checkpoint files use private `0600` permissions.

The executor passes the resolved project directory so lifecycle projects keep

checkpoints alongside their own outputs.