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]`.
TOML load/store (`ConfigStore`): `[providers]` tagged union presets, `[database]` section. Default path via platformdirs. Providers may set `timeout` as a float or `{ connect, read }` (`HttpTimeoutConfig`); omitted → product defaults (10s connect / 600s read). `DeepseekProvider.convention` (Literal: `""`/`"openai"`/`"anthropic"`/`"responses"`) selects the DeepSeek API surface — `"responses"` → OpenAI Responses, `"anthropic"` → Anthropic Messages on `https://api.deepseek.com/anthropic` (default url follows the convention); a per-model `ModelConfig.convention` overrides it (empty = inherit). `[mcp]` (`McpConfig`): `servers.<name>` stdio server definitions (`McpServerConfig`: `command`/`args`/`env`/`cwd`/`timeout`/`read_only`, `url` reserved for streamable HTTP) + `disable` gate; defining a server opts it in.
- **`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), `mcp_instructions` (fold connected MCP servers' initialize ``instructions`` into the system prompt when tools on; default true), `allow_paths` (static out-of-workspace pre-allow `path → read|write|exec`; never prompts), `auto_continue_limits` (auto-raise tool/PTY limits without prompting; default false), `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.
- **`workspace`**: path resolve under primary root **or** temporary allowlist roots **or** a directory-access grant (mode-aware: `read` < `write` < `exec`, default required `write`; a file grant matches only that file); path substring denylist (wins over grants); command basename denylist (CLI: timed human allow override, default deny on timeout; **not** skipped by YOLO); escape error hints `request_directory_access`.
- **`access`** (`tools/access.py`): `request_directory_access` (LOCAL|INSTANCE|SESSION) asks the host hook for out-of-workspace access; grants are one `path → mode` pair in one of three stores — `WorkspacePolicy.config_allow` (static `[agent].allow_paths`), `SessionState.access_grants` (human-approved, persisted on the session row), `WorkspacePolicy.yolo_allow` (`--yes`/`/yolo`, process only). `AccessDecision(mode, persist)` from the hook; denylisted paths can never be granted; cap `MAX_ACCESS_GRANTS`. Not a sandbox: `exec` grants (and any command) reach the whole FS.
- 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.
- CLI limit hooks: interactive confirm to raise tool-loop rounds, PTY session cap, or PTY output budget. The prompt accepts `y`/empty (once), `n`, or `yyy` = stop asking for the rest of the turn (`cli.limits` module flag, reset by `run_turn_with_retries`, `/btw`, session switches, and chat exit). `--auto-continue` / `[agent] auto_continue_limits` set the process-wide default (covers one-shot/PTY); the flag does not imply YOLO and vice versa.
- 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.
- **`mcp`** (`tools/mcp.py`): register one server's advertised tools into the catalog as namespaced `mcp__<server>__<tool>` definitions with `ToolSource(kind="mcp", plugin_id=server)`; tags LOCAL (+ READ_ONLY when the server config sets `read_only`) — never YOLO/TRUSTABLE. `register_mcp_tools` purges prior MCP entries then re-registers every connected server (hosts call it on tool-registry rebuild); connections must already be started by `McpManager`.
- **`DEFAULT_TOOLS` / catalog**: access + 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), `--auto-continue` (auto-raise limits), `--stream/--no-stream`, `--quiet`. Root `--log-level`. Enabled `[mcp]` servers start before the REPL (`_start_mcp_manager`, per-server failures warn on stderr) and are closed on exit (`McpManager.aclose`).
- 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. `/mcp` (`list` default) prints per-server status/tool counts + an `instructions` preview when the server sent usage guidance, + last stderr lines; `/mcp reconnect` re-reads config, restarts every enabled server, and rebuilds the tool registry. `/grants` lists directory-access grants (`revoke <index|all>`; config grants point at the TOML); `/status` includes the grant count.
-`/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. The model gets an `aside` notice as its last message before the question (unsaved exchange + tool scope), shown to the user as `[notice] aside: …`.
- Explicit `/resume` or `--session` from another workspace prompts: **keep** / **update** / **abort**. A session resumed by a **freshly started process** (`--session` / default latest) also gets a `resume` notice about what a restart drops (PTY sessions, running commands, temp workspaces) — resuming inside a live process pushes nothing.
- Host notices (`agent/notices.py`): system-level messages appended as trailing `developer` rows, never system-prompt edits — `Notice.to_message()` for the model, `.summary` for the user via `cli.display.echo_notice` (`--quiet` hides the user line only). Durable hosts persist them (`ChatAgent.push_notice`); a side agent without memory keeps its notice local. Trailing developer messages never end a turn, so `/retry` still sees an interrupted turn behind a notice or checkpoint.
- Failed/cancelled turns: user kept; **committed tool rounds kept** (side effects not re-run on `/retry`); only unfinished assistant rolled back; Ctrl+C cancels; TTY confirms off-loop; auto-retry waits 5s/10s/15s/20s then +10s (10 attempts) and the budget **resets when an attempt completes a model round** (connection recovered); then `/retry`.
- Pretty tool lines: known tools (`read_file`, `run_argv`, `grep_files`, …) print their `* Verb 'target' ` prefix as the call starts and append the outcome (`L1-4 (done)`, `(exit code 0)`) when the result lands, so a blocking tool stays visible while it runs. Interactive TTY only (`interactive_terminal()`): piped/plain output and `--verbose` keep whole lines / `[tool ok]`. A second call before the first result (parallel batch) erases the open prefix and falls back to whole lines.
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. |
