Set PTY size explicitly in python bridge fallback

.prompt-hub/lessons.md

@@ -8,3 +8,4 @@
 - Proactive terminal handshake injection can be echoed back as raw input in bridge mode; prefer startup-config mitigations over escape-sequence injection.
 - If injected terminal response sequences are echoed as raw text, stop injection and instead disable Codex startup prompts/warnings via config flags to reduce hidden interactive blockers.
 - For interactive Codex/TUI output in embedded xterm, avoid forcing `convertEol: true`; it can distort line rendering and split characters across lines.
+- Python PTY bridge must set terminal size explicitly (`TIOCSWINSZ`) using requested cols/rows; otherwise interactive TUI output can degrade into letter-per-line rendering.

.prompt-hub/memory.md

@@ -28,3 +28,4 @@
 | 2026-03-13 20:15:06 CET | agent | Added proactive Codex startup terminal handshake (immediate + delayed retry) to address blank bridge startup, with validation and governance updates. | `main.ts`, `.prompt-hub/lessons.md`, `npm run build`, `npm test`, `.prompt-hub/todo/todo-20260313-201421-codex-proactive-handshake.md`, `.prompt-hub/version.md`, `.prompt-hub/releases.md` | success | Commit and push for user retest. |
 | 2026-03-13 23:24:39 CET | agent | Removed ineffective Codex escape injection (echoed as raw input) and switched to startup prompt-suppression flags in Codex launch command; validated build/tests. | `main.ts`, `.prompt-hub/lessons.md`, `npm run build`, `npm test`, `.prompt-hub/todo/todo-20260313-232410-codex-disable-startup-prompts.md`, `.prompt-hub/version.md`, `.prompt-hub/releases.md` | success | Commit and push for user retest. |
 | 2026-03-13 23:30:56 CET | agent | Fixed broken split-character Codex rendering by disabling forced xterm EOL conversion (`convertEol: false`); validated build/tests and updated governance files. | `main.ts`, `.prompt-hub/lessons.md`, `npm run build`, `npm test`, `.prompt-hub/todo/todo-20260313-233016-fix-codex-split-characters-output.md`, `.prompt-hub/version.md`, `.prompt-hub/releases.md` | success | Commit and push for user verification. |
+| 2026-03-13 23:37:35 CET | agent | Fixed letter-per-line Codex output by propagating cols/rows to python PTY bridge and applying `TIOCSWINSZ` in explicit PTY fork/exec bridge path; validated compile/smoke/build/tests. | `pty-proxy.js`, `pty-bridge.py`, `.prompt-hub/lessons.md`, `python3 -m py_compile pty-bridge.py`, `python3 pty-bridge.py <payload>`, `npm run build`, `npm test`, `.prompt-hub/todo/todo-20260313-233621-fix-codex-pty-size-python-bridge.md`, `.prompt-hub/version.md`, `.prompt-hub/releases.md` | success | Commit and push for user retest. |

.prompt-hub/releases.md

@@ -1,5 +1,9 @@
 # Releases
 
+## 0.1.12 - 2026-03-13
+- Fixed python PTY fallback sizing by propagating requested cols/rows from the proxy and applying them in `pty-bridge.py` via `TIOCSWINSZ` at startup.
+- Reworked python bridge execution from `pty.spawn` convenience mode to explicit PTY fork/exec streaming for deterministic terminal sizing.
+
 ## 0.1.11 - 2026-03-13
 - Fixed split-character / broken newline rendering in embedded Codex output by disabling forced xterm EOL conversion (`convertEol: false`).
 

.prompt-hub/todo/todo-20260313-233621-fix-codex-pty-size-python-bridge.md

@@ -0,0 +1,19 @@
+# Task: Fix Codex letter-per-line output in python PTY bridge
+
+## Context
+- Codex output appears as one character per line in embedded terminal.
+- Likely PTY size negotiation issue in python fallback bridge.
+
+## Plan
+- [x] Pass cols/rows through proxy payload to python bridge.
+- [x] Replace bridge spawn path with explicit PTY fork + winsize setup.
+- [x] Validate build/tests and update traceability.
+
+## Review
+- Updated `pty-proxy.js` to pass normalized `cols`/`rows` into python bridge payload.
+- Reworked `pty-bridge.py` to use explicit PTY fork/exec and apply terminal size (`TIOCSWINSZ`) before streaming.
+- Validation:
+  - `python3 -m py_compile pty-bridge.py` passed.
+  - `python3 pty-bridge.py <payload>` smoke test passed (`OK_BRIDGE`).
+  - `npm run build` passed.
+  - `npm test` passed (`12/12` tests).

.prompt-hub/version.md

@@ -1 +1 @@
-0.1.11
+0.1.12

pty-bridge.py

@@ -3,7 +3,11 @@ import base64
 import json
 import os
 import pty
+import fcntl
+import select
+import struct
 import sys
+import termios
 
 
 def decode_payload(raw: str):
@@ -21,6 +25,42 @@ def as_exit_code(status: int) -> int:
     return 1
 
 
+def set_winsize(fd: int, rows: int, cols: int) -> None:
+    packed = struct.pack("HHHH", rows, cols, 0, 0)
+    fcntl.ioctl(fd, termios.TIOCSWINSZ, packed)
+
+
+def stream_pty(pid: int, fd: int) -> int:
+    stdin_open = True
+    while True:
+        readers = [fd]
+        if stdin_open:
+            readers.append(sys.stdin.fileno())
+
+        ready, _, _ = select.select(readers, [], [])
+        if fd in ready:
+            try:
+                chunk = os.read(fd, 4096)
+            except OSError:
+                chunk = b""
+            if not chunk:
+                break
+            os.write(sys.stdout.fileno(), chunk)
+
+        if stdin_open and sys.stdin.fileno() in ready:
+            try:
+                chunk = os.read(sys.stdin.fileno(), 4096)
+            except OSError:
+                chunk = b""
+            if not chunk:
+                stdin_open = False
+            else:
+                os.write(fd, chunk)
+
+    _, status = os.waitpid(pid, 0)
+    return as_exit_code(status)
+
+
 def main() -> int:
     payload = decode_payload(sys.argv[1] if len(sys.argv) > 1 else "")
 
@@ -35,6 +75,10 @@ def main() -> int:
         os.environ[str(key)] = str(value)
 
     launches = payload.get("launches") or []
+    cols = int(payload.get("cols") or 120)
+    rows = int(payload.get("rows") or 30)
+    cols = max(20, cols)
+    rows = max(10, rows)
     if not launches:
         print("[py-bridge-error] no launch specs provided", file=sys.stderr)
         return 1
@@ -45,8 +89,12 @@ def main() -> int:
         args = launch.get("args") or []
         argv = [str(file)] + [str(x) for x in args]
         try:
-            status = pty.spawn(argv)
-            return as_exit_code(status)
+            pid, fd = pty.fork()
+            if pid == 0:
+                os.execvpe(str(file), argv, os.environ)
+
+            set_winsize(fd, rows, cols)
+            return stream_pty(pid, fd)
         except OSError as error:
             failures.append(f"{file}: {error}")
 

pty-proxy.js

@@ -139,7 +139,9 @@ function spawnPythonBridge(payload, launches) {
     JSON.stringify({
       cwd: payload.cwd,
       env: payload.env,
-      launches
+      launches,
+      cols: payload.cols,
+      rows: payload.rows
     }),
     "utf8"
   ).toString("base64");
@@ -185,7 +187,9 @@ async function main() {
           term = spawnPythonBridge(
             {
               cwd: payload.cwd,
-              env: fallbackEnv
+              env: fallbackEnv,
+              cols: Math.max(20, Number(payload.cols) || 120),
+              rows: Math.max(10, Number(payload.rows) || 30)
             },
             launches
           );