Vellum Terminal Sessions

What the source does

• FilesystemNone observedNo reads or writes in the source
• NetworkNone observedNo outbound calls in the source
• ShellNone observedNo commands run in the source
• DependenciesPinnedNothing floats
• SecretsNone foundNo keys in source

Five audit layers

Gates applied: no behavioural pass.

assistant/CLAUDE.md

assistant/src/approvals/CLAUDE.md

assistant/src/notifications/CLAUDE.md

assistant/src/runtime/CLAUDE.md

gateway/CLAUDE.md

Audit 0.4.1 · source sha 19bc86343b63 · 14 Oct 2026Report an issue or request a re-scan

• Publishervellum-ai GitHub organizationOwner of the repository this skill is read from
• Source foldervellum-ai/vellum-assistant/skills/vellum-terminal-sessionsThe exact folder we audited
• LicenceMITAs the repository states it
• Commit pinned for this verdict19bc86343b63A new audit runs when the source changes
• Repository statusNot archivedLast push 1 day ago
• Sandboxed runNot runSkills are read, not executed; layer L4 is skipped

Its description: Manage persistent tmux terminal sessions: create, read, write to, list, and close named shell sessions. For Claude Code or Codex, use the ACP skill instead.

---
name: vellum-terminal-sessions
description: "Manage persistent tmux terminal sessions: create, read, write to, list, and close named shell sessions. For Claude Code or Codex, use the ACP skill instead."
compatibility: "Sandbox mode works without any host dependencies. Host mode requires tmux installed on the user's machine. Works on macOS and Linux."
metadata:
  emoji: "🖥️"
  author: vellum-ai
  version: "0.2"
  vellum:
    category: "system"
    display-name: "Terminal Sessions"
    activation-hints:
      - "User asks about their running terminal sessions or processes"
      - "User wants to monitor a long-running command or run something in a persistent shell"
      - "User mentions tmux or terminal management"
      - "User wants to orchestrate multiple CLI processes in parallel"
    avoid-when:
      - "Setting up, authenticating, or running Claude Code or Codex: the ACP skill owns those agents"
      - "A simple one-shot command that host_bash handles fine"
      - "The user is asking about shell scripting in general, not session management"
---

## Overview

This skill manages **persistent terminal sessions** via tmux. Two modes:

|                       | Sandbox Mode                                  | Host Mode                                                           |
| --------------------- | --------------------------------------------- | ------------------------------------------------------------------- |
| **Where tmux runs**   | In the assistant's sandbox                    | On the user's host machine                                          |
| **How user connects** | `vellum terminal attach <session-name>`       | User opens their own terminal                                       |
| **Assistant access**  | Direct (`bash` tool)                          | Via `host_bash`                                                     |
| **Best for**          | Long-running builds, servers, always-on tasks | Work needing host access (e.g. SwiftUI builds, host-local services) |

**Default:** Use **Sandbox Mode** unless the task specifically requires host access. Details: [sandbox-sessions.md](references/sandbox-sessions.md) · [host-sessions.md](references/host-sessions.md) · [tmux-best-practices.md](references/tmux-best-practices.md)

## Prerequisites

**Sandbox Mode:** No setup needed — tmux is available in the sandbox.

**Host Mode:** Requires tmux on the host — see [host-sessions.md](references/host-sessions.md).

## Workflow: Orchestrating Multiple Sessions

- **List** all sessions: `tmux list-sessions` to get names and current commands
- **Read** each: `tmux capture-pane -t NAME -p -S -50` (30-50 lines is usually enough)
- **Summarize** before acting: "Build done, tests at 73%, deploy waiting for confirmation"
- **Act** on the user's instructions

Excerpt, first 2,813 characters of SKILL.md, verbatim from the audited commit. It is text from someone else’s repository, quoted so you can judge it before your agent reads it.

1. 2026-10-14
   ✓SAFE B 89 / 100

   first audit · source 19bc86343b63

Questions about Vellum Terminal Sessions

• github.com/vellum-ai/vellum-assistant/tree/main/skills/vellum-te — the audited source at commit 19bc86343b63 and every finding aboveObserved · 14 Oct 2026

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