docs: document ask-family argument shape checks

AGENTS.md

@@ -94,7 +94,7 @@ Module-level `@tool` handlers. Call `set_workspace_root()` before use.
 - 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).
 - **`vcs`**: read-only VCS tools (`vcs_kind` / `vcs_status` / `vcs_diff` / `vcs_log` / `vcs_branch`) via `VcsBackend` protocol; **git** implemented; detectors are pluggable for other systems.
-- **`chat`**: human prompts as tools — `ask_user_line` / `ask_user_choice` / `ask_user_form` (shared `prompting` core); `wait` (line prompt with timeout; Enter disturbs).
+- **`chat`**: human prompts as tools — `ask_user_line` / `ask_user_choice` / `ask_user_form` (shared `prompting` core); `wait` (line prompt with timeout; Enter disturbs). Container args are shape-checked (`tools/chat/shape.py`): a mis-typed string `options`/`fields` (or a non-string `question`) returns an explained error — `options="a, b"` used to iterate characters into a per-character menu.
 - **`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`.

README.md

@@ -300,6 +300,8 @@ Safety defaults:
   `write_pty` is literal text only; use `write_pty_keys` for `\xHH`, `ctrl+x`, `key=esc|enter|…`.
   For passwords/sudo/ssh prompts use `ask_into_pty` (human types locally; answer never returns to the model).
 
+- Mis-typed tool arguments are answered, never guessed: a string where an array is expected (`run_argv` `argv`, `ask_user_choice` `options`, `ask_user_form` `fields`) returns an error that shows the shape to send — the human is not shown a garbage prompt.
+
 ## Usage / context (CLI)
 
 - **Context size** prefers API `prompt_tokens` from the last model call; otherwise a char-based estimate (~4 chars/token).