docs: cover session deletion, side-question tools, and subagent model prose

Document the Ctrl-X delete in the session picker, the read-only tools a
/btw side question may call, that the subagent timeout also governs tower
workers and reviewers, and how the reserved primary alias is rendered.

Author: elkaix

docs/configuration/config-files.md

@@ -244,7 +244,7 @@ Pool aliases reference the current `[models]` table. If a provider is deleted or
 
 In the interactive TUI, the [`/secondary-model`](../reference/slash-commands.md) command (alias `/subagent-model`) opens a model selector: the choice is written to `default_model` (when a models table exists and the picked alias is not in it, an entry with an empty description is added), and newly spawned subagents pick up the new default immediately — no session restart needed.
 
-A configured pool — an explicit `models` table or a lone `default_model` — enables model selection: the `Agent` / `AgentDynamicWorkflow` tools gain a `model` parameter, and the tool description lists the pool (the default marked `[default]`) so the main agent can choose per spawn. Pool keys can only reference configured [`[models]`](#models) entries:
+A configured pool — an explicit `models` table or a lone `default_model` — enables model selection: the `Agent` / `AgentDynamicWorkflow` tools gain a `model` parameter, and the tool description lists the pool (the default marked `[default]`) so the main agent can choose per spawn. The reserved alias `primary` is listed as `primary (= <alias>)`, naming the model the main agent is running on; pool entries do not inherit the main agent's thinking level. Pool keys can only reference configured [`[models]`](#models) entries:
 
 ```toml
 [secondary_model]
@@ -387,7 +387,7 @@ In print mode (`pythinker -p "<prompt>"`), Pythinker Code stays alive after the
 
 | Field | Type | Default | Description |
 | --- | --- | --- | --- |
-| `timeout_ms` | `integer` | `7200000` (2 hours) | Maximum wall-clock time (milliseconds) a single `Agent` subagent is allowed to run before it is settled as `timed_out`. `0` means no timeout — the subagent runs until it finishes or the model stops it. This is the background-task manager's per-task timeout for each subagent task, so it applies to both foreground and background subagents. In print mode (`pythinker -p`) the default is `0` unless explicitly set. Note: any value above `2147483647` (about 24.8 days) is clamped to roughly 24.8 days by the runtime |
+| `timeout_ms` | `integer` | `7200000` (2 hours) | Maximum wall-clock time (milliseconds) a single `Agent` subagent is allowed to run before it is settled as `timed_out`. `0` means no timeout — the subagent runs until it finishes or the model stops it. This is the background-task manager's per-task timeout for each subagent task, so it applies to foreground subagents, background subagents, and tower workers and reviewers. In print mode (`pythinker -p`) the default is `0` unless explicitly set. Note: any value above `2147483647` (about 24.8 days) is clamped to roughly 24.8 days by the runtime |
 
 `timeout_ms` can be overridden by the `PYTHINKER_SUBAGENT_TIMEOUT_MS` environment variable, which takes higher priority than `config.toml`.
 

docs/guides/sessions.md

@@ -59,7 +59,7 @@ pythinker --session
 You can manage sessions without leaving the terminal. The following slash commands are available only when the agent is idle:
 
 - **`/new`** (alias `/clear`): switch to a new session, discarding the current context.
-- **`/sessions`** (alias `/resume`): browse and resume a previous session.
+- **`/sessions`** (alias `/resume`): browse and resume a previous session. Press `Ctrl-X` on a row to delete that session; the picker asks for confirmation and stays open until the deletion finishes. Deleting the session you are in closes it and starts a fresh one.
 - **`/fork`**: fork the current session (see below).
 - **`/title <text>`** (alias `/rename`): set a session title for easier identification; without arguments, displays the current title.
 

docs/reference/slash-commands.md

@@ -109,7 +109,7 @@ Prompt mode exits with code `0` when the goal completes, `3` when it blocks, and
 | Command | Alias | Description | Always available |
 | --- | --- | --- | --- |
 | `/help` | `/h`, `/?` | Show keyboard shortcuts and all available commands | Yes |
-| `/btw [question]` | — | Open a side conversation in a forked sub-Agent without affecting the current main Agent turn; without a question, opens the panel first to wait for input | Yes |
+| `/btw [question]` | — | Open a side conversation in a forked sub-Agent without affecting the current main Agent turn; the side Agent may call the read-only `Read`, `Grep`, and `Glob` tools, and every other tool is rejected; without a question, opens the panel first to wait for input | Yes |
 | `/usage` | — | Show token usage, context consumption, and quota information | Yes |
 | `/status` | — | Show the current session runtime state: version, model, working directory, permission mode, etc. | Yes |
 | `/mcp` | — | List MCP servers and their connection status in the current session | Yes |