Distillation

Date: Sep 8, 2026

• 🟡 (10:33) /home/byk/.local/share/opencode-v2-pilot/supervisor/cmd/launcher/main.go defines encodedArgumentsEnvironment = "OPENCODE_PTY_ARGV" and launcherFD = 3. run() accepts the special --exec path, otherwise validates encoded arguments, calls syscall.Fchdir(2), replaces fd 2 via syscall.Dup2(1, 2), installs the fixed environment, stores dot-joined arguments in OPENCODE_PTY_ARGV, calls bindLauncher(), and executes /usr/bin/script.
• 🟡 (10:33) execCommand() in /home/byk/.local/share/opencode-v2-pilot/supervisor/cmd/launcher/main.go rejects a missing OPENCODE_PTY_ARGV, decodes its dot-separated arguments, resets the fixed environment, closes fd 3, and calls syscall.Exec(command[0], command, os.Environ()).
• 🟡 (10:33) bindLauncher() in /home/byk/.local/share/opencode-v2-pilot/supervisor/cmd/launcher/main.go opens /proc/self/exe with unix.O_RDONLY|unix.O_CLOEXEC; it binds that executable to fd 3 using unix.Dup3(fd, launcherFD, 0), or clears FD_CLOEXEC with unix.FcntlInt(..., unix.F_SETFD, 0) when the opened descriptor is already fd 3.
• 🟡 (10:33) decodeArguments() in /home/byk/.local/share/opencode-v2-pilot/supervisor/cmd/launcher/main.go permits at most protocol.MaxArgs+1 encoded values; requires each to begin with a; accepts only raw URL-safe Base64 grammar [A-Za-z0-9_-]; verifies canonical re-encoding; rejects NUL bytes; applies protocol.MaxCommandSize to index 0, protocol.MaxArgSize to later values, and protocol.MaxArgsSize to aggregate argument bytes.
• 🟡 (10:34) A patch successfully modified /home/byk/.local/share/opencode-v2-pilot/config/opencode/plugins/pty.ts.
• 🟡 (10:34) /home/byk/.local/share/opencode-v2-pilot/config/opencode/package.json is private, uses "type": "module", depends on effect via file:/home/byk/Code/opencode-v2-pilot/node_modules/.bun/effect@4.0.0-rc.112/node_modules/effect, and has @types/bun version 1.2.21 as a dev dependency.
• 🟡 (10:35) /home/byk/.local/share/opencode-v2-pilot/config/opencode/tsconfig.json uses allowImportingTsExtensions: true, libraries ESNext, DOM, and DOM.Iterable, module: "Preserve", moduleResolution: "Bundler", noEmit: true, skipLibCheck: true, strict: true, target: "ESNext", and types ["bun"]; it includes plugins/**/*.ts and test/**/*.ts.
• 🟡 (10:35) TypeScript path mappings in /home/byk/.local/share/opencode-v2-pilot/config/opencode/tsconfig.json map @opencode/plugin to /home/byk/Code/opencode-v2-pilot/packages/plugin/src/promise/index.ts and @opencode/plugin/* to /home/byk/Code/opencode-v2-pilot/packages/plugin/src/promise/*.ts.
• 🟡 (10:36) Assistant stated the direct PTY backend was in place and was being checked against the frozen smoke contract and candidate service/cutover files before removal of the abandoned transport.
• 🟡 (10:36) The inspected /home/byk/.local/share/opencode-v2-pilot/config/opencode/plugins/pty.ts defines requireSession() to require both a matching session ID and matching parentSessionID; helper functions include lineCount(), lastNonblankLine(), linePage(), truncate(), decodeEscapes(), and shellCommand().
• 🟡 (10:36) decodeEscapes() in /home/byk/.local/share/opencode-v2-pilot/config/opencode/plugins/pty.ts decodes \xNN, \uNNNN, \n, \r, \t, and \\; shellCommand() single-quotes the command and every argument and escapes embedded single quotes as '\\''.
• 🟡 (10:36) The fallback openPtyProcess() in /home/byk/.local/share/opencode-v2-pilot/config/opencode/plugins/pty.ts:526-627 spawns SCRIPT_PATH with ["-q", "-e", "-f", "-c", \printf '%s\n' "$$" >&3; exec 3>&-; exec ${shellCommand(command, args)}`, "/dev/null"], uses cwd /proc/self/fd/${directory.fd}`, runs detached, and exposes 4 piped stdio streams.
• 🟡 (10:36) openPtyProcess() uses environment values HOME=/home/byk, LANG=C.UTF-8, LOGNAME=byk, PATH=/usr/bin:/bin, SHELL=SHELL_PATH, TERM=xterm-256color, and USER=byk; this fallback PATH differs from the supervisor launcher’s /usr/local/bin:/usr/bin:/bin.
• 🟡 (10:36) openPtyProcess() buffers combined UTF-8 stdout/stderr up to MAX_BUFFER_SIZE, reads the command PID from fd 3, requires PID text matching ^[1-9][0-9]*\n$ and at most 32 characters, and kills the detached process group with SIGKILL if PID acquisition fails.
• 🟡 (10:36) The returned PtyProcess.close() first sends SIGTERM to both the command process group and wrapper process group, waits TERMINATE_TIMEOUT_MS, then sends SIGKILL to both and throws PTY process ${pid} did not close. if another TERMINATE_TIMEOUT_MS wait fails. Exit codes 143 and 137 are mapped to SIGTERM and SIGKILL.
• 🟡 (10:36) signalProcessGroup() in /home/byk/.local/share/opencode-v2-pilot/config/opencode/plugins/pty.ts:629-636 calls process.kill(-pid, signal) and ignores only ESRCH.
• 🟡 (10:36) terminate() in /home/byk/.local/share/opencode-v2-pilot/config/opencode/plugins/pty.ts:638-647 is idempotent for exited/killed or already-terminating sessions, sets status to "killing", applies CLOSE_TIMEOUT_MS to session.process.close(), then separately requires session.closed to settle within CLOSE_TIMEOUT_MS.
• 🟡 (10:36) authorize() in /home/byk/.local/share/opencode-v2-pilot/config/opencode/plugins/pty.ts:660-700 canonicalizes the requested workdir and project directory, requests external_directory permission when outside the project, requests shell permission for the fully quoted command, rechecks the workdir after approval, opens it with constants.O_RDONLY | constants.O_DIRECTORY | constants.O_NOFOLLOW, verifies it is a directory, and confirms /proc/self/fd/${handle.fd} still resolves to the approved directory.
• 🟡 (10:36) validateCommand() in /home/byk/.local/share/opencode-v2-pilot/config/opencode/plugins/pty.ts:702-719 rejects an empty command, command or arguments containing NUL bytes, more than MAX_ARGUMENTS, commands exceeding MAX_COMMAND_LENGTH UTF-8 bytes, individual arguments exceeding MAX_ARGUMENT_LENGTH UTF-8 bytes, and aggregate argument bytes exceeding MAX_ARGUMENT_BYTES; its errors report actual argument counts or byte lengths.
• 🟡 (10:36) assertShell() in /home/byk/.local/share/opencode-v2-pilot/config/opencode/plugins/pty.ts:721-732 requests shell permission for either the original quoted command or a resource formatted as ${shellCommand(session.command, session.args)} <stdin> ${shellCommand(input, [])}, with an empty save list and tool source metadata.
• 🟡 (10:36) matchingLines() in /home/byk/.local/share/opencode-v2-pilot/config/opencode/plugins/pty.ts:751-789 runs /usr/bin/grep with -a -m <limit> -nE, optional -i, and -- <pattern>; it kills grep after 250 ms, caps stdout at MAX_BUFFER_SIZE * 2 and stderr at MAX_LINE_LENGTH, treats exit code 1 as no matches, and parses results into { line, text } records.