Streaming: Chinese reasoning showed up garbled in the WebUI. The agent
loop now feeds visible/thinking text in runs instead of byte by byte,
and the WebUI holds an incomplete UTF-8 tail until the next chunk
(cst_utf8_hold_feed), so every think_delta/assistant_delta is whole.
src/provider_switch.c: model list fetch/cache, key verify-and-save and
provider switching moved out of tui.c and shared by TUI and WebUI.
WebUI API:
- GET /api/providers, GET /api/models[?refresh=1] (401 on a rejected
key, still listing built-ins), POST /api/provider, POST /api/key
(key checked against /v1/models, saved to credentials 0600, never
echoed in replies, events or logs)
- /api/config validates everything before applying, persists model,
effort and approval (not yolo), warns when effort does not apply;
plan_mode no longer forces read-only
- state: turn_usage, api_base, key_set/key_from, model_info,
effort_applies, sees_images, max_steps, tool_profile, perm_timeout;
permission events carry their timeout
Frontend: searchable model picker with refresh and manual entry,
provider picker and key dialog, effort/vision hints, toasts instead of
silent failures, Chinese error text, real protocol in the settings and
usage panels, approval countdown from the server's timeout.
Tests: utf8 hold unit test, scripts/e2e_webui_settings.py (fake
/v1/models, wrong key, switching, persistence, Chinese thinking) run
from e2e_webui.sh, scripts/tui_keys/provider.py.
Build: <fcntl.h> in tui.c, format-truncation in http_srv.c and /web.
WebUI:
- refuse cross-site requests (Origin must be the page itself) in the
default no-token mode: any page could POST approval=yolo and a prompt
- session/workspace/undo/compact/attach/model changes are 409 while a
turn runs (use-after-free, messages landing in the wrong session)
- ask_user returned "dismissed" at once instead of waiting
- cancel and shutdown wake a turn parked on a permission or question;
SIGTERM mid-turn no longer hangs or crashes
- a page opened while a question is pending still gets it;
Last-Event-ID resumes the stream; event seq matches the SSE id
- token mode: page assets load without the token, images via cookie
- --web-open works, --web-port/--web-token are validated
- frontend: gate keys ignored while typing, clear-images button,
reasoning no longer wiped while streaming
HTTP server: auth and size cap before reading the body, strict
Content-Length, NUL in url_decode, 413 on keep-alive, idle timeout,
absolute-form only without a leading '/', case-insensitive Connection,
header deadline, 400 for long request lines, unlink before close,
poll() instead of select(), SO_EXCLUSIVEADDRUSE on Windows.
Markdown sanitizer escapes quotes in attribute values.
/web: passes this session's provider/model/base/effort/approval (key
via the environment), keeps output off the TUI, shows the real URL and
keeps CURRENT on the TUI's session.
Tests: scripts/e2e_webui_ask.py, scripts/e2e_webui_http.py (run from
e2e_webui.sh), sanitizer quote test.
A second implementation of cst_agent_hooks_t next to the TUI: the turn runs on
a worker thread, the hooks publish events into a ring buffer that SSE clients
read, so the engine itself needs no changes.
- src/net.c, include/cst_net.h: POSIX/Winsock sockets, non-blocking connect
- src/http_srv.c, include/cst_http.h: HTTP/1.1, keep-alive, chunked streaming,
body caps (413), Expect: 100-continue, connection cap, exact routing
- src/web_md.c, include/cst_web_md.h: streaming markdown -> sanitized HTML
(tag/attribute allowlist, javascript: URLs and off-site images dropped)
- src/webui.c, include/cst_webui.h: event ring + SSE broadcast, all routes,
token (Bearer/Cookie/query) and loopback Host checks, 3 s auto-deny when no
client is attached
- src/webui_stub.c, CST_WEBUI=0 / CST_BUILD_WEBUI=OFF: build without the WebUI
- web/: no-build front end (transcript, approvals, todo, sessions, image
upload, status bar)
- docs/webui.md: engine API v1 - events, requests, security model
- tests/test_webui.c, scripts/e2e_webui.sh: unit tests plus an end-to-end run
driven by a recorded SSE stream (no API key needed)
- src/main.c: --web --web-port --web-host --web-token --web-dev --web-open
and CST_WEB_PORT/HOST/TOKEN/ROOT
An empty POST body is now accepted without Content-Length (RFC 9112 6.3) so
curl-driven clients can reach cancel/undo/compact/quit; CMakeList's core tests
learned about sashidown and test_webui, and CST_WEBUI=0 defines CST_NO_WEBUI.
TUI keys: register both CSI and SS3 forms of the cursor/Home/End keys and
the xterm modifier sequences when terminfo lacks them, so an arrow sent in
the "other" form no longer turns into Esc + a typed letter. Up/Down move by
visual (soft-wrapped) row, and the draft survives a trip through history.
scripts/tui_keys drives the TUI in a pty to check all of this.
Images: text inside a multimodal content array is now a {"type":"text"}
part; DeepSeek rejected the bare string with HTTP 422. deepseek-flash
(and its deepseek-chat / deepseek-reasoner aliases) read images, so the
registry marks them vision; deepseek-v4-pro stays text only.
CI: models.c lost _DEFAULT_SOURCE in 0.7.0 and gmtime_r broke the musl
build; tests sleep with poll() instead of usleep for the same reason.
Landlock no longer handles TCP, the Seatbelt profile drops (deny network*),
and the seccomp filter stops refusing IPv4/IPv6 sockets. Sandboxed commands
run without asking in auto mode on every backend (Low-IL no longer asks for
network commands), and connection errors are not treated as sandbox blocks.
Images
- vision gate: text-only models get a note instead of image parts and no
view_image tool; unknown models retry once without images on HTTP 400
- paste: Ctrl+V and /attach paste read the clipboard (wl-paste, xclip,
pngpaste/osascript, Win32 PNG or CF_DIB converted to PNG); pasting image
file paths attaches them
- MCP image content is stored in the session and sent with the tool result
- attach: rel path validation, base64 decode, /retry keeps images
Model registry
- built-in src/models_builtin.json embedded at build time, merged with
<config>/models.json and cached GET /models metadata (context, vision,
pricing); most specific rule wins per field
- /model labels, /status source, --list-models [provider]
Cache and cost
- stable request prefix (frozen tools, notes as messages), DeepSeek prefix
completion, OpenAI/Anthropic cache hints, /cost and hit rate in the status
clang under strict C11 left strcasestr undeclared (returns int → pointer
truncation → SIGSEGV). Parse Content-Length portably; keep -Werror on
make check. Drop Nix for windows-cross (root /nix fails) and use pinned
llvm-mingw UCRT instead; Alpine musl gets linux-headers for audit.h.
test_subagent segfaulted in the Docker runner: the fake SSE handler took
user + strlen(user) - 1 with an empty user string. Guard JSON access and
format the child report with an empty-safe last character. Remove the
sanitizers job entirely (if: false still queued it and blocked the runner).
With Yama ptrace_scope=2 and no CAP_SYS_PTRACE, process_vm_readv and
/proc/<pid>/mem both fail, so sc_decide cannot read path strings and every
workspace write gets EACCES. The old probe only checked the USER_NOTIF
round trip, so CST_SANDBOX=seccomp and the forced-seccomp test pass looked
available and then failed on the first write.
sc_can_peek() forks a child, places a marker on its stack, and retries the
same sc_peek path. sc_probe() now needs that too, so those hosts fall back
to none (or keep landlock) instead of a silent deny-all sandbox.
os_temp_dir() used $TMPDIR or "/tmp" without checking either. On Termux
/tmp usually does not exist (or SELinux denies it) unless TMPDIR points at
$PREFIX/tmp, so plugin and MCP temp files failed and shell children that
need a temp file (heredocs) broke.
* os_temp_dir() picks, once, the first of $TMPDIR, $PREFIX/tmp, /tmp,
/var/tmp and ~/.cache/cst-agent/tmp where a file can really be
created; if none works it keeps the old answer
* os_temp_dir_export() at startup writes the choice back to TMPDIR, so
shell children and the sandbox's writable temp dir agree
* tests/test_tmpdir.c covers the fallbacks in fresh forks
Build
* cross build switches to pkgsCross.ucrt64 (shell-win.nix); curl (Schannel),
winpthreads and ncurses 6.6 are linked statically, so the release is
cst-agent.exe + busybox.exe (busybox-w32 Unicode) with no extra DLLs
* windres embeds a manifest with activeCodePage=UTF-8 and a version resource
* ncurses 6.6 Windows console driver patches (mouse button state, A_DIM,
wide-char declarations): scripts/patches/
* scripts/bootstrap_msys2.sh builds the same release natively in MSYS2
UCRT64; PR #1's MINGW64 notes now point there
* vendor/tre-regex (musl's TRE) provides <regex.h> on MinGW
UTF-8
* paths cross the system call boundary as UTF-16 (*W APIs); console code
pages set to 65001 and restored on exit; files are read and written in
binary mode
* child output that is not valid UTF-8 is decoded from the console, OEM or
ANSI system code page
* read_file hides CR; edit_file, apply_patch and write_file keep CRLF line
endings and a UTF-8 BOM
OS layer and processes
* os_dir_* and cst_fnmatch replace the POSIX-only directory walks in
subagent, plugins, skills, undo and fs_tools; realpath / path_under and
symlink rejection work on Windows
* every child goes through CreateProcessW with its own environment block
inside a Job Object, so timeouts and Esc end the whole process tree
Sandbox (auto mode, "auto · lowil")
* run_shell runs with a restricted Low integrity token; the workspace gets
an inheritable Low label once, the sandbox TEMP is labeled Low, and the
credentials file gets a no-read-up label
* drive roots, the profile and system folders are never labeled
* network commands still ask, since Low IL does not block the network;
Access denied and MSYS2's 0xc0000142 offer a rerun outside the sandbox
* /sandbox lists labeled folders, /sandbox reset-labels restores them
TUI
* raster console fonts are switched to Consolas / NSimSun while running
* the home logo falls back to text when the console font lacks U+2580
* mouse drag copy goes to the Windows clipboard
Distribution
* scripts/install_windows.ps1 installs a Gitea release into
%LOCALAPPDATA%\Programs\cst-agent and adds it to the user PATH;
cst-agent-update.cmd reruns it; scripts/release_windows.sh uploads the
zip with the token taken from the environment
* scripts/run_windows.bat is gone; docs/README-windows.md is rewritten
Tests
* new test_lowil, test_win_utf8 and test_os_dir; tests made portable
(cst_test_util.h)
* scripts/win_test.sh and scripts/winvm/ run the suite on English and
Chinese Windows Server VMs as Administrator, a standard user and a
Chinese user name: 29/29 on all six
- Drag, double-click (word) and triple-click (line) selection in the log,
auto-scroll at the edges, soft-wrapped lines joined on copy.
- sashidown ANSI renderer: delimiter runs with flanking rules, so
intraword underscores (test_apply_patch.c) stay literal; unmatched
* _ and backticks are shown as-is; * and _ do not close each other.
- tests: test_textsel, test_markdown.
Query CSI ? u at startup and push the disambiguate flag on the alternate
screen when the terminal answers; CSI u reports are mapped back to legacy
input (Shift/Ctrl+Enter insert a newline, Ctrl+Backspace deletes a word).
Ctrl/Alt+Left/Right move by word, Ctrl/Alt+Delete delete the next word.
Our define_key codes move above the range ncurses uses for terminfo
extended keys.
- Child installs a seccomp filter with a listener; a supervisor thread
resolves the path of write-type syscalls (cwd, dirfd, .., symlinks,
/proc/self, /dev/stdout, both ends of rename/link) and answers
CONTINUE or EACCES; IPv4/IPv6 sockets are refused
- Probe order Landlock -> seccomp -> none, checked in a throwaway child;
CST_SANDBOX=landlock|seccomp|off
- curl connect failures count as sandbox refusals
- test_sandbox runs the detected sandbox and forced seccomp, with escape,
symlink, rename, link, chmod, stdout, ENOENT, background and network cases
- Docs: platform matrix, limits (not a security boundary, Yama and
background jobs)
Tools
- Table-driven tool registry with permission classes and default/minimal
profiles; new tools: edit_file, list_dir, glob, grep, delete_file,
move_file, todo_write, web_fetch, ask_user (plus read_file paging).
- Built-in Myers diff; write tools return unified diffs.
- Persistent permission rules (.agent/permissions.json), per-turn undo
snapshots (.agent/undo), AGENTS.md project notes, auto-compact at 80%
of the model context, cancellable run_shell with process-group kill.
TUI
- Table-driven slash commands: /provider /key /effort /status /tools
/permissions /yolo /undo /retry /diff /export /copy /rename /delete
/init /max-steps /todo, with / and @ completion.
- Permission modal with diff and prefix rules, ask_user modal, todo
panel, header with model/effort/context, bracketed paste, line editing,
wide-char cursor, NO_COLOR and ASCII fallback; Esc never quits.
Startup and configuration
- API keys are entered in the TUI (hidden) and saved per provider in
<config>/credentials (0600); env variables are only a fallback.
- Last provider, per-provider model and reasoning effort are remembered
in <config>/settings.json; --effort/-e and /effort send
reasoning_effort (low|medium|high|max) to models that accept it.
- DeepSeek preset uses deepseek-flash / deepseek-v4-pro.
- Session flags --new/--continue/--resume/--list-sessions, --yolo,
--confirm.
Compatibility and tests
- ncurses detection, macOS/Homebrew support, make install, XDG config
dir, POSIX cleanups; Gitea CI (gcc/clang/asan/musl/macOS).
- Unit tests for diff, fs tools, registry, undo/perms and config;
e2e fixtures multi_file_refactor and ask_or_todo; vendored cJSON.
WHC