# Workspace internals

## Purpose
Define the local durable and run-local workspace model used by stages, manifests, resume, and archive.

## Inputs and Outputs
Inputs:
- `pipeline.workspace.root`
- `session.campaign`
- `session.session_id`
- generated `run_id`

Outputs:
- Session manifest at `{workspace.root}/work/{campaign}/{session_id}/manifest.json`
- Run manifest at `{workspace.root}/work/{campaign}/{session_id}/runs/{run_id}/manifest.json`
- Canonical durable session directories and run-local stage trees

## Boundaries
Owns:
- Session-level path layout (`inputs/`, `audio/`, `transcripts/`, `artifacts/`, `reports/`, `logs/`, `config/`, `current/`, `runs/`, `previous/`)
  - `previous/manifest.json` and `previous/artifacts/**` are reserved for prepared previous-session state
- Run-local stage sandbox layout under `runs/{run_id}/{stage}/`
- Session lock acquisition/release (`.lock`)

Does not own:
- Stage business logic
- Remote archive semantics (documented in `stage-archive.md`)
- CLI argument parsing

## Config Fields Used
- `pipeline.workspace.root`
- `pipeline.workspace.cleanup_after_archive`
- `pipeline.spool.root`
- `pipeline.spool.delete_audio_after_archive`
- `session.campaign`
- `session.session_id`

## External Adapters Used
None directly in this subsystem. Stages may use object storage adapters and then write local outputs into this layout.

## State and Manifest Behavior
- Session state is persisted in the session manifest (`manifest.Manifest`).
- Invocation history is persisted per run in run manifests under `runs/{run_id}/manifest.json`.
- During each run, stage outputs are often written run-local first (`runs/{run_id}/{stage}/outputs/...`) and promoted to canonical session paths after stage success.
- `manifest.Artifacts` entries record `ProducerRunID` for durable outputs.
- For S3 audio sessions, `prepare` records spool/work paths and S3 provenance in `manifest.Inputs`.

## Skip and Resume Behavior
- Skip/resume decisions are made in `internal/app` (`run_control.go`, `resume.go`) using stage status in the session manifest.
- `--force` reruns selected stages and marks downstream previously-succeeded stages as `stale`.
- Workspace layout is idempotent (`EnsureLayoutFor`) and reused across runs.

## Failure Behavior
- Failures preserve manifests and run-local files for inspection.
- Lock conflicts fail fast via `ErrLockConflict`.
- Cleanup can fail post-archive; failure is recorded in archive stage metadata and returned by the run.

## Tests to Inspect Before Changing
- `internal/artifacts/local_test.go`
- `internal/stage/run_local_test.go`
- `internal/app/run_control_test.go`
- `internal/app/resume_run_stage_test.go`
- `internal/app/post_archive_cleanup_test.go`

## Architectural Invariants
- Session root is campaign-aware: `{workspace.root}/work/{campaign}/{session_id}`.
- Run roots are always nested: `runs/{run_id}` under the session root.
- Run-local output promotion must end in canonical session paths.
- `previous/**` is session-durable state and must not be treated as run-local output scratch state.
- Cleanup only targets run-scoped directories and must never delete configured root directories.