Plyngent is an LLM chat and agent toolkit (Python 3.14+, PDM-managed). Single-user CLI is usable: protocol clients, config, async memory, agent tool loop, workspace tools, and REPL/one-shot chat. Multi-tenant `router/` / web remain Phase H.
GitHub Actions runs `ruff check`, `ruff format --check`, `basedpyright`, then `pytest`. Local commits run the same checks via `prek.toml` so `ruff format` is not forgotten.
All protocol models use `msgspec.Struct` — not dataclasses, not Pydantic. Optional fields use `msgspec.field(default=UNSET)` / `default=UNSET` with type `T | Unset`.
`typedef.py`: `Unset = UnsetType` (plain assignment so msgspec recognizes it; do **not** use PEP 695 `type Unset = ...`). Multi-struct unions must be **tagged** via `tag_field` / `tag` (e.g. `role`, `type`) for decode. `JSONSchema` is `dict[str, Any]`.
- **`messages_bridge` / `messages_dispatch`**: chat ↔ Anthropic Messages; system fold; tool_use/tool_result; stream text + tool argument fragments.
- **Provider-side tools**: `OpenAIProvider.provider_tools` (list of dicts; default `[{type="web_search"}]` when omitted; `[]` disables) threaded via `ChatAgent`/`run_chat_loop` into Responses only; never executed by `ToolRegistry`.
- **`ChatAgent`**: optional `MemoryStore` (user message persisted immediately; **completed tool batches checkpointed** mid-turn; unfinished assistant suffix rolled back on failure); `stream`; system prompt; `provider_tools`; `retry()` continues incomplete turns (user-only **or** after committed tools — does not re-run those tools).
- **`/compact`**: soft-compact tool dumps → model summary (no tools) via the same kind dispatch → **new** session seeded with summary message. Soft-compact keeps the last **12** tool results full-size by default (`DEFAULT_RECENT_TOOL_RESULTS`); older tool payloads shrink first.
- Config ``[agent]``: `system_prompt` (persona; default `DEFAULT_SYSTEM_PROMPT`; `""` omits persona), `tool_directives` (tool playbook; default `DEFAULT_TOOL_DIRECTIVES`; `""` omits playbook; both empty → no system), `max_tool_result_chars`, `parallel_tools`, `confirm_destructive`, `path_denylist`, `max_context_tokens` (default 200k est. tokens). Truncated tool results carry a model hint (`[Truncated (N chars max; M omitted). You may ask for user to increase the limit via configuration file.]`) so the model can ask the user to raise `max_tool_result_chars`; request-time compact shrinks (`hint=False`) keep the terse `...[truncated N characters]` marker.
- PTY: backend in `pty_backend.py`; structured status (`alive`/`exit_code`/`data`); `read_pty(..., until=)` (**CSI sanitized** so host TTY is never reset); keys via `write_pty_keys` only (`\xHH`, `ctrl+x`, `key=esc`); secrets via `ask_into_pty` (not `write_pty` data); session limit/idle TTL/output budget; close terminate→kill.
- Destructive confirms: `classify_danger` + `ToolRegistry(on_confirm=…)`; CLI default deny; config `confirm_destructive` / `path_denylist`. Soft confirm also for shells/REPLs and `python|bash -c` one-liners (argv + code preview); deny may include a user comment for the model. Session YOLO: `/yolo on|off|once` and `--yes` (skip soft confirms; hard denylists unchanged; `once` expires after the next user turn).
- **`todo`**: LIFO stack of **task groups** (not a queue of tasks) — `todo_push` creates one group of siblings; `todo_pop` removes the whole top group; `todo_update` by id; DFS breakdown push[T1,T2]→push[T1.1…]→pop→push[T2.1…]; stored on session row; open items = unfinished work (`[TODO OPEN WORK]`); all-terminal non-empty = hygiene (`[TODO HYGIENE]`); nag channel via `[agent] todo_nag_strategy` (`developer`/`user` = prose nag; `synthetic_tool` = forged `todo_list` call + **real**`stack.render()` result + ToolCall/Result events; `none`).
- **`net` / `fetch`**: HTTP GET/POST/PUT/DELETE via niquests (isolated session, not the LLM client). Manual redirects with per-hop SSRF checks (`asyncio``getaddrinfo`). Private/loopback hosts need instance policy grant (CLI timed confirm; **not** YOLO). Public cleartext HTTP and mutating methods soft-confirm (`YOLO`/`TRUSTABLE`). HTTPS→HTTP redirects blocked unless `allow_http_downgrade`. `user_agent` tool arg (or headers) is never replaced by the default when provided. Caps: body bytes/chars, request body size.
- **`DEFAULT_TOOLS` / catalog**: file + process + vcs + chat + todo + net (`fetch`) for local surface. `ToolTag.READ_ONLY` marks non-mutating tools (`read_file`, `get_truncated`, `listdir`, `glob_paths`, `grep_files`, `tree`, `todo_list`, `wait`, `ask_user_*`, `vcs_*`, `fetch`); `ToolRegistry.clone(read_only_only=True)` selects just those for safe side turns / planning, and `read_only_context()` (in `tools/context.py`) makes `fetch` accept GET only.
- **`plyngent chat`**: provider/model (flags or interactive; Tab via readline in `prompting`); sessions store `provider_name`/`model` and restore on resume; SQLite via `[database]` (file DB under user data when url unset; explicit `url = ":memory:"` kept + warn); workspace-bound; resume latest for cwd/`--workspace` by default (`--new` / `--session`). One-shot: `-p/--prompt` and non-TTY stdin; exit codes 0/1/2/3; `--yes` (YOLO on), `--stream/--no-stream`, `--quiet`. Root `--log-level`.
- Slash: Click group in `cli/slash.py` + `awaitlet` for async work; Tab completer from registry + ParamType `shell_complete`. Multiline `"""` … `"""`; `/edit` via `$VISUAL`/`$EDITOR` (blocking only). `/yolo on|off|once` for soft destructive confirms. `/model --persist` / `/models --persist` write model catalog entries into TOML. `/todos` for human show/push/pop/clear of the todo stack.
-`/btw` side questions: forked session; main transcript/DB untouched. `--tools=read` (default) exposes only `READ_ONLY` tools under `read_only_context()` (fetch=GET) with the main session view; `--tools=no` off; `--tools=full` whole-registry clone with fresh session. Tools off: default falls back to no tools; explicit `read`/`full` errors.
Today `PtyManager` (`tools/process/pty_session.py`) is **in-process**: `pty.openpty` + `os.fork` → child `execvp`, parent holds master FD; `read_pty`/`close_pty` run via `to_thread`. Session registry is process-global. Safe enough for single-user CLI if the child path stays fork-then-exec only.
| Separate PTY supervisor process so the main app is safer with threads/greenlets? | **Not for Phase G.** Defer to **Phase H** (sandbox / multi-tenant) or if we hit real FD-leak / freeze bugs. |
| Why not now? | Fork-then-exec is already the right shape; rewrite cost (IPC, lifecycle, tests) dwarfs single-user CLI risk. awaitlet greenlets are slash-only; PTY is not forked from a worker thread today. |
