Terminal Control: Control, inspect, test, and capture terminal sessions

Terminal Control, a new open-source tool by Kit Langton, enables AI agents to control, inspect, test, and capture real terminal sessions via pseudo-terminals. The Rust-based tool supports named sessions, visible-screen reads, exact keyboard input, and video recording, allowing coding agents to interact with TUIs and CLIs without guessing from plain command output. It is designed for agent workflows and requires Rust 1.93 or newer.

Control, inspect, test, and capture real terminal applications for agents and TUI review. Saved from one live OpenCode session using start , send , and save . Terminal Control is built for agents first. Install the termctrl binary, install the skill, then ask your coding agent to operate terminal applications through a real pseudo-terminal instead of guessing from plain command output. Requires Rust 1.93 or newer. Video export also requires ffmpeg . cargo install terminal-control termctrl --help Install the current repository head instead of the latest crate release: cargo install --locked --git https://github.com/kitlangton/terminal-control terminal-control Install the agent skill from this repository: npx skills add kitlangton/terminal-control --skill terminal-control Then ask your agent for terminal work in ordinary language: Use terminal-control to open my TUI, press through the setup flow, and save a screenshot of the final screen. Start two terminal sessions: one running the dev server and one running the CLI. Drive the CLI until it connects, then show me both screens. Record yourself using the terminal app, mark the important moments, and export a short MP4 demo. The skill teaches agents the safe workflow: start named sessions, wait for visible text, send exact input, inspect screens, save artifacts, record timelines, mark important moments, export videos, and stop sessions when finished. - Real PTY control for TUIs, shells, curses apps, OpenTUI apps, and long-running CLIs. - Named background sessions so an agent can keep multiple terminals alive and switch between them. - Visible-screen reads through show , not brittle scraping of scrollback or logs. - Exact keyboard and text input with send , including arrows, tabs, enter, escape, page keys, and ctrl-a through ctrl-z . - Explicit waits for rendered text before interacting. - Resizing to test responsive terminal layouts. - Evidence capture as PNG, SVG, text, JSON, or ANSI when requested. - Recording timelines with markers, edited MP4 export, and optional branded footers for demos and bug reports. - Local-only owner-protected session sockets and explicit warnings around sensitive terminal artifacts. Read a one-off terminal screen: termctrl show --cols 100 --rows 32 -- my-terminal-app Save evidence: termctrl save --format png --format txt --out captures/home -- my-terminal-app Drive a persistent TUI session: termctrl start demo --host opentui --cols 112 --rows 34 -- opencode termctrl wait demo "Ask anything" --timeout 20000 termctrl send demo --pace-ms 35 'text:Write a terminal haiku.' enter termctrl show demo termctrl stop demo Record and export a video: termctrl start demo --host opentui --record captures/demo.termctrl -- opencode termctrl wait demo "Ask anything" termctrl mark demo ready termctrl send demo --pace-ms 35 'text:Write a short terminal haiku. End with DONE.' enter termctrl wait demo "DONE" --timeout 60000 termctrl mark demo after-answer termctrl stop demo termctrl video captures/demo.termctrl --edit captures/demo.json --out captures/demo.mp4 The sections below explain each workflow in more detail. Requires Rust 1.93 or newer. Video export also requires ffmpeg . cargo install terminal-control termctrl --help Install the current repository head instead of the latest crate release: cargo install --locked --git https://github.com/kitlangton/terminal-control terminal-control Run a program in a PTY and print its visible terminal state: termctrl show --cols 100 --rows 32 -- my-terminal-app Show is the routine observation command: it prints visible text to standard output and creates no files. Request a different stdout-readable representation explicitly: termctrl show --format json -- my-terminal-app termctrl show --format svg -- my-terminal-app Wait for an application to mount, then interact before reading its screen: termctrl show --cols 100 --rows 32 --wait-for "Commands" \ -s ctrl-p text:model enter -- my-terminal-app OpenTUI applications such as OpenCode require the opt-in host handshake: termctrl show --host opentui --cols 112 --rows 34 \ --wait-for "/connect" -- opencode Write only the artifact formats you request: termctrl save --format png --out captures/home.png -- my-terminal-app termctrl save --format png --format txt --out captures/model -- my-terminal-app The second command writes captures/model.png and captures/model.txt . ANSI stream artifacts can contain sensitive terminal data and are only produced when explicitly requested with --format ansi . Use a named session when several observations or interactions should target the same running application: termctrl start demo --host opentui --cols 112 --rows 34 -- opencode termctrl status demo termctrl wait demo "/connect" --timeout 5000 termctrl show demo termctrl send demo text:/connect enter termctrl resize demo --cols 132 --rows 38 termctrl wait demo "Connect a provider" --timeout 5000 termctrl show demo termctrl save demo --format png --out captures/provider.png termctrl stop demo status reports running or exited , the effective working directory, command, viewport, and recording path. An exited session retains its final screen for show until it is stopped. list distinguishes unavailable stale sockets from incompatible older session protocols. send accepts ctrl-a through ctrl-z , keys such as enter , escape , arrows, tab , shift-tab , backspace , delete , home , end , page-up , and page-down , plus typed input as text:<value . Use ctrl-c to interrupt work or pipe exact prompt bytes with --stdin : printf '%s' 'Summarize the active view.' | termctrl send demo --stdin resize controls the terminal viewport and records geometry changes in .termctrl timelines when recording is enabled. A session whose retained ANSI transcript has already been truncated cannot be resized because its current screen cannot be replayed at a new size safely. For normal-screen tools and long-running log processes, inspect retained scrollback directly: termctrl logs demo termctrl logs demo --ansi captures/demo-output.ansi Full-screen alternate-screen TUIs do not provide useful terminal logs; read their visible screen with show or retain a recording timeline instead. Status exposes logs truncated after raw retained ANSI reaches --max-bytes ; the session continues running and retains its most recent transcript bytes. Restart a single named owner safely when deploying updated code: termctrl restart demo restart NAME reuses the prior command, effective working directory, viewport, host profile, color policy, and recording path by default. Supply options or a replacement command only when deliberately changing the launch. Record a session timeline and replay it as an MP4: termctrl start demo --record captures/demo.termctrl \ --host opentui --cols 112 --rows 34 -- opencode termctrl wait demo "Ask anything" termctrl mark demo before-prompt termctrl send demo --pace-ms 35 'text:Write a short terminal haiku. End with the uppercase form of done.' enter termctrl wait demo "DONE" --timeout 60000 termctrl mark demo after-answer termctrl save demo --format png --out captures/answer.png termctrl stop demo termctrl markers captures/demo.termctrl termctrl show --recording captures/demo.termctrl --at-marker after-answer termctrl video captures/demo.termctrl --edit captures/demo.json --footer --tail-ms 0 --hide-cursor --out captures/demo.mp4 The marker-based edit plan is explicit and deterministic. speed accelerates or slows the real recorded time inside that clip. caption adds a visible annotation row. hold ms is optional and creates a deliberate still frame at the end of a clip; omit it when you do not want artificial freezes. { "clips": { "from": "before-prompt", "to": "after-answer", "speed": 4, "caption": "The agent answers inside the live terminal UI" } } Without --edit , video export preserves the observed recording timing. Edit plans are preferable for polished demos because they select intentional marker ranges and can accelerate animated spinner spans without relying on visual-idle heuristics. Keep speeds low enough for important terminal text to remain readable, and add hold ms or leave a --tail-ms hold when the final screen is the point of the demo. Identical rendered screens are rasterized once and reused during export. Video export trims startup frames before non-whitespace text by default while still preserving recordings that only paint terminal backgrounds; use --include-startup to keep all startup frames. video holds the final frame for one second by default so short recordings do not end abruptly; pass --tail-ms 0 for a strict no-holds cut. Pass --footer to put the clip caption, elapsed timecode, and TERMINAL CONTROL branding in a bottom footer instead of rendering captions as inline annotation rows. Use termctrl markers captures/demo.termctrl to audit available marker names and timestamps. Use termctrl show --recording captures/demo.termctrl --at-marker after-answer or --at-ms 1234 to inspect exact screens while tuning an edit plan. Recordings are JSON Lines files containing terminal output, client input, and automatic host input; they can include prompts or secrets. Treat them as sensitive artifacts. Repeat --format to export only what you need: termctrl save --format png --format txt --out captures/home -- my-terminal-app Read a current visible screen directly for agent inspection, or select JSON/ANSI/SVG explicitly: termctrl show demo termctrl show demo --format json For commands whose useful output is piped, use --pipe . Pipe reads force color by default; pass --color never for plain output: termctrl save --pipe --format png --format txt --cols 100 --rows 16 \ --out captures/log -- my-command One-off show and save operations own disposable command processes: once the visible screen is read or saved, the launched process tree is terminated. Use start for long-running applications. Render an existing ANSI/VT terminal stream without launching a process. An .ansi file is a conventionally named byte stream of terminal output and escape sequences, not a separate container format: printf '\033 44;97m terminal output \033 0m\n' | termctrl show --input - printf '\033 44;97m terminal output \033 0m\n' | termctrl save --input - --format png --out captures/stdin.png The crate also exposes the shot engine, live sessions, and artifact model to Rust callers. The CLI is built on the same terminal control::shot , terminal control::session , terminal control::frame , terminal control::render , and terminal control::recording modules: js let shot = terminal control::shot::from ansi b"\x1b 32mready\x1b 0m".to vec , 1, 20, 1024 ?; assert eq shot.frame.text , "ready" ; let svg = terminal control::render::svg &shot.frame, &terminal control::render::Options::default ; A library session keeps one PTY-backed application in process for fast test interaction without repeatedly invoking the CLI: js use std::time::Duration; let mut session = terminal control::session::Session::start & "my-terminal-app".to owned , None, None, &terminal control::shot::Options::default , ?; session.wait for text "Ready", Duration::from secs 5 ?; let status = session.status ?; session.send b"help\r" ?; session.wait for idle Duration::from millis 250 , Duration::from secs 5 ?; let capture = session.capture Duration::from millis 250 , Duration::from secs 5 ?; let shot = capture.shot; let exit = session.wait for exit Duration::from secs 5 ?; session.stop ?; Structured output is versioned for external tools: - A save --format json capture is a Frame object with version: 1 , described by schemas/frame-v1.schema.json . - A .termctrl recording is JSON Lines: its first line is a versioned header and subsequent lines are timed output, input, or resize entries, each described by schemas/recording-entry-v1.schema.json . - Recording byte arrays contain the original terminal or input bytes as integers from 0 to 255 ; recordings can contain sensitive text or input. session::Session is the embedded lifecycle interface; the flat named-session CLI commands and the external driver are adapters over the same implementation. External agent tooling can keep multiple embedded sessions alive through a versioned JSON Lines protocol over stdin/stdout: termctrl driver The driver writes a hello message with protocol and Terminal Control versions, then accepts typed operations including launch , status , send , waitForText , waitForIdle , waitForExit , capture , logs , recording , resize , stop , and shutdown . It is intended for clients such as a TypeScript TUI test or agent-control library, while the shell-facing flat commands remain convenient for individual workflows. {"type":"hello","protocolVersion":1,"terminalControlVersion":"<installed-version "} {"id":1,"method":"launch","sessionId":"app","params":{"command": "my-terminal-app" ,"cols":100,"rows":30,"inheritEnv":false,"env":{"TERM":"xterm-256color"}}} {"id":2,"method":"waitForText","sessionId":"app","params":{"text":"Ready","timeoutMs":5000}} {"id":3,"method":"send","sessionId":"app","params":{"input": {"type":"text","value":"help"},{"type":"key","value":"enter"} }} {"id":4,"method":"capture","sessionId":"app","params":{"settleMs":250,"deadlineMs":5000}} A driver capture response contains a structured visible frame, derived text , and a completion reason : idle , deadline , exited , or outputclosed . Raw ANSI is omitted by default; request includeAnsi: true for retained transcript bytes or includeSvg: true for rendered visual evidence. A test client should normally require idle or exited instead of accepting a deadline fallback as a stable snapshot. Driver input is intentionally exact: text, raw bytes, known key values, and single-letter control input are supported without claiming unimplemented key chords. @kitlangton/terminal-control exposes the driver as isolated typed test sessions. It deliberately separates the visible screen from readable retained logs and the exact ANSI/VT transcript. Its npm distribution includes an optional native package for macOS or GNU/Linux on arm64 or x64, so consumers do not need a Rust toolchain or separate termctrl installation. After the initial npm publication: bun add -d @kitlangton/terminal-control vitest js import { TerminalControl } from "@kitlangton/terminal-control" await using terminal = await TerminalControl.make { artifacts: { directory: ".termctrl-artifacts", onFailure: true, includeTranscript: false, includeRecording: true, }, } await using session = await terminal.launch { command: "/absolute/path/to/my-terminal-app" , viewport: { cols: 100, rows: 30 }, inheritEnv: false, env: { TERM: "xterm-256color", HOME: "/tmp/test-home" }, record: "on-failure", } await session.screen.waitForText /Ready/ await session.keyboard.type "help" await session.keyboard.press "Enter" const text = await session.screen.text const frame = await session.screen.frame const logs = await session.logs.text const transcript = await session.transcript.ansi expect text .toMatchSnapshot expect frame .toMatchSnapshot const exit = await session.waitForExit { timeoutMs: 5 000 } expect exit .toMatchObject { reason: "exited", exit: { code: 0 } } When working directly from this repository before installing the npm artifacts, pass binaryPath: "./target/release/termctrl" or set TERMCTRL BINARY . session.screen.text and session.screen.frame wait for a settled capture and reject deadline or output-closed fallback by default. A test that intentionally needs an intermediate frame can request it explicitly: js const capture = await session.screen.capture { allowIncomplete: true } console.log capture.reason, capture.text, capture.frame This makes ordinary text or frame snapshots stable by default while retaining explicit access to live, incomplete terminal state. Keyboard presses are typed as the sequences Terminal Control encodes exactly, such as "Enter" , "ArrowDown" , or "Control+C" . Use session.keyboard.write bytes when a test deliberately needs exact terminal bytes outside that supported key set. Vitest users can add a screen-aware assertion that writes configured artifacts on failure. Standard toMatchSnapshot and toMatchInlineSnapshot remain the simplest snapshot format because visible text is reviewable in source control: js import { expect } from "vitest" import { extendTerminalControlMatchers } from "@kitlangton/terminal-control/vitest" extendTerminalControlMatchers expect await expect session .toHaveScreenText "Ready\n\nChoose an option" await expect session.screen.text .resolves.toMatchInlineSnapshot session.writeArtifacts name and failing toHaveScreenText ... assertions can write screen.txt , screen.json , screen.svg , logs.txt , and metadata.json . Environment variable values are redacted in metadata. transcript.ansi and recording.termctrl are opt-in because terminal streams and typed input may contain secrets. Wrap ordinary snapshot assertions when evidence should be saved on any thrown assertion: js await session.withArtifactsOnFailure "settings-snapshot", async = { await expect session.screen.text .resolves.toMatchSnapshot } Enable a recording with record: true or record: "on-failure" ; a test may explicitly save it before disposing the session: await session.resize { cols: 120, rows: 40 } await session.saveRecording "artifacts/navigation.termctrl" The npm workspace publishes @kitlangton/terminal-control with fixed-version platform packages: @kitlangton/terminal-control-darwin-arm64 , @kitlangton/terminal-control-darwin-x64 , @kitlangton/terminal-control-linux-arm64-gnu , and @kitlangton/terminal-control-linux-x64-gnu . The client is compiled to ESM JavaScript with declarations; each native package receives the release Rust executable during the npm release workflow. For subsequent user-facing npm changes, create a Changeset with bun run changeset , commit the generated release metadata, run bun run version-packages , refresh bun.lock , and commit the versioned package metadata before running the workflow. Run the workflow with publish: false to assemble packages only, or publish: true to publish assembled tarballs after its clean Bun and Node/Vitest consumer validation passes. The publish job is prepared for npm trusted publishing through GitHub Actions OIDC. In npm package settings, configure kitlangton/terminal-control and workflow npm-release.yml as the trusted publisher for the client and each platform package before using publish: true . - Persistent sessions use owner-only local Unix sockets and are supported on macOS and Linux. --host opentui answers startup probes needed by current OpenTUI applications; Kitty graphics are reported unavailable because the current renderer does not decode image payloads.- The current renderer uses a pure-Rust vt100 terminal backend and exports PNG, SVG, JSON, text, and raw ANSI stream artifacts. - Run termctrl <command --help for dimensions, timing, color, rendering, and output options.