# Contributor handoff — AUTOMATIC1111/stable-diffusion-webui

> Canonical page: https://codevetter.com/unpack/stable-diffusion-webui/agent-handoff

# Contributor handoff — AUTOMATIC1111/stable-diffusion-webui

Scanned commit 82a973c04367123ae98bd9abdf80d9eda9b910e2 (2024-07-27). Generated by codevetter codevetter 1.12.0 on 2026-09-22.

Read webui.py, modules/initialize.py, modules/processing.py, modules/scripts.py, modules/shared.py, and modules/paths_internal.py first — they define the boot order, the p-object pipeline, and the global-state conventions everything else hangs off. Safe edit zones: scripts/ and extensions-builtin/ for new features; modules/api/api.py + modules/api/models.py for new endpoints; shared_options.py for new settings. Traps: import-order sensitivity (paths_internal before torch), the single queue_lock serialization, opts restore semantics, and test mode requiring --test-server conventions.
- Import-order discipline matters: modules/paths_internal.py and modules/cmd_args.py parse sys.argv at import time and inject COMMANDLINE_ARGS; shared_cmd_options imports launch.py and runs extension preload.py files at import — never import torch-dependent modules before initialize.imports(), and set IGNORE_CMD_ARGS_ERRORS=1 when running pytest/other tools. — [modules/paths_internal.py#L12-13](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/paths_internal.py#L12-L13) [modules/shared_cmd_options.py](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/shared_cmd_options.py) [modules/cmd_args.py#L22](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/cmd_args.py#L22) [test/conftest.py](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/test/conftest.py)
- Follow the 'p' convention: generation features should be implemented as Script subclasses (scripts/ or extension scripts/) mutating the StableDiffusionProcessing object via the documented hook lifecycle, not by editing process_images_inner directly — the base class docstrings define exactly when each hook fires. — [modules/scripts.py#L52-348](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/scripts.py#L52-L348) [modules/processing.py#L863-1150](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/processing.py#L863-L1150)
- Adding a REST endpoint: add a pydantic model in modules/api/models.py, register with self.add_api_route in Api.__init__ (auto-wraps Depends(auth) when --api-auth is set), reuse init_script_args/apply_infotext for generation endpoints, and wrap generation calls in self.queue_lock. — [modules/api/api.py#L199-251](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/api/api.py#L199-L251) [modules/api/api.py#L274-284](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/api/api.py#L274-L284) [modules/api/models.py](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/api/models.py)
- Adding a setting: add an OptionInfo entry to the right options_section in modules/shared_options.py (or shared.options_templates.update from an extension); set restrict_api=True to hide it from /sdapi/v1/options; onchange callbacks run via opts.set(); do_not_save entries never persist. — [modules/shared_options.py](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/shared_options.py) [modules/options.py#L14-34](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/options.py#L14-L34) [modules/options.py#L144-171](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/options.py#L144-L171)
- Code style is ruff-governed (pyproject.toml: target py39, select B/C/I/W, E501/E721/E731/C901 ignored, extensions/ excluded); run 'ruff .' and 'npm run lint' before committing; CI also requires PRs from forks (lint/test jobs skip same-repo PRs). — [pyproject.toml](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/pyproject.toml) [package.json](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/package.json) [.github/workflows/on_pull_request.yaml](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/.github/workflows/on_pull_request.yaml)
- To run tests locally you must boot the app first: 'python launch.py --test-server --skip-prepare-environment --skip-torch-cuda-test --use-cpu all --api-server-stop' then 'pytest test' — tests hit a live server on :7860, there is no offline unit-test path for the pipeline. — [.github/workflows/run_tests.yaml](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/.github/workflows/run_tests.yaml) [test/conftest.py](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/test/conftest.py) [modules/launch_utils.py#L449-460](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/launch_utils.py#L449-L460)
- Beware mutable module globals: shared.sd_model may be swapped mid-generation by refiner/override_settings (reload_model_weights is called inside the batch loop); shared.opts changes during a job are restored by process_images' finally block only if override_settings_restore_afterwards — keep new opts writes inside that contract. — [modules/processing.py#L826-860](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/processing.py#L826-L860) [modules/processing.py#L941](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/processing.py#L941)
- Infotext is the cross-cutting serialization format: paste_fields in modules/infotext_utils.py map infotext labels ↔ gradio components ↔ API fields; any new generation parameter must be added there (and to create_infotext's generation_params dict) to roundtrip through PNG metadata and 'Send to' buttons. — [modules/infotext_utils.py](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/infotext_utils.py) [modules/processing.py#L750-816](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/processing.py#L750-L816)
- File-not-found and extension errors should go through modules/errors.py report()/display() (they render in UI and log), not bare exceptions; scripts' callback failures are individually caught by script_callbacks report_exception so one bad extension doesn't kill the run. — [modules/errors.py](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/errors.py) [modules/script_callbacks.py#L14-15](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/script_callbacks.py#L14-L15) [modules/scripts.py#L533-535](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/scripts.py#L533-L535)
- Device/memory plumbing is centralized in modules/devices.py (autocast, torch_gc, test_for_nans, dtype selection via --no-half/--precision/--use-cpu) and modules/lowvram.py (--lowvram/--medvram model shuffling) — new GPU work should reuse devices.get_optimal_device/autocast/without_autocast contexts rather than raw torch calls. — [modules/devices.py](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/devices.py) [modules/lowvram.py](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/lowvram.py) [modules/shared_init.py](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/shared_init.py) [modules/cmd_args.py#L74-75](https://github.com/AUTOMATIC1111/stable-diffusion-webui/blob/82a973c04367123ae98bd9abdf80d9eda9b910e2/modules/cmd_args.py#L74-L75)

Every claim links to its cited files at the pinned commit. Citations identify source evidence; they do not establish runtime correctness. Independent CodeVetter scan — not reviewed by upstream maintainers.

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