diff --git a/pi-coding-agent-input.el b/pi-coding-agent-input.el
index 23f7a6e..edf8e5b 100644
--- a/pi-coding-agent-input.el
+++ b/pi-coding-agent-input.el
@@ -310,12 +310,16 @@ The /compact command is handled locally; other slash commands sent to pi."
   (interactive)
   (let* ((text (string-trim (buffer-string)))
          (chat-buf (pi-coding-agent--get-chat-buffer))
-         (transitioning (and chat-buf
+         (chat-live-p (buffer-live-p chat-buf))
+         (transitioning (and chat-live-p
                              (pi-coding-agent--session-transition-active-p
                               chat-buf)))
-         (busy (and chat-buf (pi-coding-agent--session-busy-p chat-buf))))
+         (busy (and chat-live-p
+                    (pi-coding-agent--session-busy-p chat-buf))))
     (cond
      ((string-empty-p text) nil)
+     ((not chat-live-p)
+      (message "Pi: No chat session available"))
      (transitioning
       (message "Pi: Cannot send while session is switching"))
      ((and busy (pi-coding-agent--builtin-command-text-p text))
@@ -331,11 +335,11 @@ The /compact command is handled locally; other slash commands sent to pi."
 
 (defun pi-coding-agent-abort ()
   "Abort the current pi operation.
-Works while streaming or compacting."
+Works while sending, streaming, or compacting."
   (interactive)
   (when-let* ((chat-buf (pi-coding-agent--get-chat-buffer)))
     (let ((status (buffer-local-value 'pi-coding-agent--status chat-buf)))
-      (when (memq status '(streaming compacting))
+      (when (memq status '(sending streaming compacting))
         (when (eq status 'streaming)
           (with-current-buffer chat-buf
             (pi-coding-agent--set-aborted t)))
@@ -388,12 +392,16 @@ Includes both built-in commands and commands from pi's `get_commands' RPC."
   (when (and (eq (char-after (point-min)) ?/)
              (> (point) (point-min)))
     (let* ((start (1+ (point-min)))
-           (end (point))
+           (end (save-excursion
+                  (goto-char start)
+                  (skip-chars-forward "^ \t\n")
+                  (point)))
            (builtin-names (mapcar #'car pi-coding-agent--builtin-commands))
            (rpc-names (mapcar (lambda (cmd) (plist-get cmd :name))
                               pi-coding-agent--commands))
            (commands (delete-dups (append builtin-names rpc-names))))
-      (list start end commands :exclusive 'no))))
+      (when (<= start (point) end)
+        (list start end commands :exclusive 'no)))))
 
 ;;;; Editor Features: File Reference (@)
 
@@ -479,15 +487,9 @@ Triggers when @ is typed, provides completion of project files."
                           (point)))))
     (let* ((start (1+ at-pos))
            (end (point))
-           (prefix (buffer-substring-no-properties start end))
-           (files (pi-coding-agent--get-project-files))
-           (candidates (if (string-empty-p prefix)
-                           files
-                         (cl-remove-if-not
-                          (lambda (f) (string-match-p (regexp-quote prefix) f))
-                          files))))
-      (when candidates
-        (list start end candidates
+           (files (pi-coding-agent--get-project-files)))
+      (when files
+        (list start end files
               :exclusive 'no
               :annotation-function (lambda (_) " (file)")
               :company-kind (lambda (_) 'file))))))
diff --git a/pi-coding-agent-menu.el b/pi-coding-agent-menu.el
index 3846aba..2979e9f 100644
--- a/pi-coding-agent-menu.el
+++ b/pi-coding-agent-menu.el
@@ -656,6 +656,14 @@ handled, even when the response failed."
                     (pi-coding-agent--finish-session-transition
                      generation)))))))))))
 
+(defun pi-coding-agent--discard-reload-process (proc)
+  "Detach and terminate temporary reload process PROC."
+  (when (processp proc)
+    (pi-coding-agent--unregister-display-handler proc)
+    (when (process-live-p proc)
+      (delete-process proc))
+    (pi-coding-agent--cleanup-process-stderr-buffer proc)))
+
 ;;;###autoload
 (defun pi-coding-agent-reload ()
   "Reload the current session by restarting the pi process.
@@ -675,6 +683,7 @@ buffer from session history."
       (message "Pi: No session to reload"))
      ((not session-file)
       (message "Pi: No session file available - cannot reload"))
+     ((not (pi-coding-agent--session-transition-ready-p chat-buf "reload")))
      (t
       (message "Pi: Reloading...")
       (with-current-buffer chat-buf
@@ -699,8 +708,12 @@ buffer from session history."
                  new-proc
                  (list :type "switch_session" :sessionPath session-path)
                  (lambda (response)
-                   (when (pi-coding-agent--session-transition-current-p
-                          chat-buf new-proc generation)
+                   (when (or (pi-coding-agent--session-transition-current-p
+                              chat-buf new-proc generation)
+                             (progn
+                               (pi-coding-agent--discard-reload-process
+                                new-proc)
+                               nil))
                      (let* ((data (plist-get response :data))
                             (cancelled (plist-get data :cancelled)))
                        (if (and (eq (plist-get response :success) t)
diff --git a/pi-coding-agent-render.el b/pi-coding-agent-render.el
index 59771b0..8c8def0 100644
--- a/pi-coding-agent-render.el
+++ b/pi-coding-agent-render.el
@@ -1223,6 +1223,9 @@ Updates buffer-local state and renders display updates."
              (plist-get message :content))))
          (_
           ;; Assistant message - show header if needed, reset markers
+          (setq pi-coding-agent--line-parse-state 'line-start
+                pi-coding-agent--in-code-block nil
+                pi-coding-agent--streaming-table-candidate nil)
           (unless pi-coding-agent--assistant-header-shown
             (pi-coding-agent--append-to-chat
              (concat "\n" (pi-coding-agent--make-separator "Assistant") "\n"))
diff --git a/pi-coding-agent-table.el b/pi-coding-agent-table.el
index 56207a4..e914b51 100644
--- a/pi-coding-agent-table.el
+++ b/pi-coding-agent-table.el
@@ -130,6 +130,9 @@ visible after streaming while hidden."
       (setq pi-coding-agent--table-decoration-pending nil)
       (setq pi-coding-agent--last-table-display-width width)
       (let ((gc-cons-threshold (max gc-cons-threshold (* 8 1024 1024))))
+        ;; Known macOS NS limitation: shrinking a scrolled chat frame can move
+        ;; the top visible line after overlay rewrapping.  Reproduce with
+        ;; `pi-coding-agent-gui-test-table-resize-refreshes-hot-tail-only'.
         (pi-coding-agent--with-scroll-preservation
           (save-excursion
             (pi-coding-agent--refresh-hot-tail-tables width)))))))
@@ -300,6 +303,8 @@ When `pi-coding-agent-prettify-tables' is non-nil, emits Unicode
 box-drawing verticals instead of markdown pipes."
   (let* ((num-cols (length col-widths))
          (padded (append cells (make-list (max 0 (- num-cols (length cells))) "")))
+         (aligns (append aligns
+                         (make-list (max 0 (- num-cols (length aligns))) nil)))
          (wrapped-cells
           (cl-mapcar (lambda (cell column-width)
                        (markdown-table-wrap-cell (or cell "") column-width))
@@ -345,30 +350,56 @@ box-drawing verticals instead of markdown pipes."
   "Render the separator line for COL-WIDTHS and ALIGNS.
 When `pi-coding-agent-prettify-tables' is non-nil, emits a box-drawing
 rule (├─┼─┤) directly; otherwise emits standard markdown syntax."
-  (if pi-coding-agent-prettify-tables
-      (concat "├─" (mapconcat (lambda (w) (make-string (max 1 w) ?─))
-                              col-widths "─┼─")
-              "─┤")
-    (let ((parts
-           (cl-mapcar
-            (lambda (column-width align)
-              (let ((dashes (make-string (max 1 column-width) ?-)))
-                (pcase align
-                  ('left
-                   (if (>= column-width 2)
-                       (concat ":" (substring dashes 1))
-                     ":"))
-                  ('right
-                   (if (>= column-width 2)
-                       (concat (substring dashes 1) ":")
-                     ":"))
-                  ('center
-                   (if (>= column-width 3)
-                       (concat ":" (substring dashes 2) ":")
-                     (if (>= column-width 2) "::" ":")))
-                  (_ dashes))))
-            col-widths aligns)))
-      (concat "| " (mapconcat #'identity parts " | ") " |"))))
+  (let* ((num-cols (length col-widths))
+         (aligns (append aligns
+                         (make-list (max 0 (- num-cols (length aligns))) nil))))
+    (if pi-coding-agent-prettify-tables
+        (concat "├─" (mapconcat (lambda (w) (make-string w ?─))
+                                col-widths "─┼─")
+                "─┤")
+      (let ((parts
+             (cl-mapcar
+              (lambda (column-width align)
+                (if (zerop column-width)
+                    ""
+                  (let ((dashes (make-string column-width ?-)))
+                    (pcase align
+                      ('left
+                       (if (>= column-width 2)
+                           (concat ":" (substring dashes 1))
+                         ":"))
+                      ('right
+                       (if (>= column-width 2)
+                           (concat (substring dashes 1) ":")
+                         ":"))
+                      ('center
+                       (if (>= column-width 3)
+                           (concat ":" (substring dashes 2) ":")
+                         (if (>= column-width 2) "::" ":")))
+                      (_ dashes)))))
+              col-widths aligns)))
+        (concat "| " (mapconcat #'identity parts " | ") " |")))))
+
+(defun pi-coding-agent--table-full-grid-p ()
+  "Return non-nil when tables should render a full web-style cell grid.
+Requires both `pi-coding-agent-prettify-tables' and
+`pi-coding-agent-table-full-grid' to be enabled."
+  (and pi-coding-agent-prettify-tables
+       pi-coding-agent-table-full-grid))
+
+(defun pi-coding-agent--render-table-grid-rule (col-widths position)
+  "Render a horizontal box-drawing rule for COL-WIDTHS.
+POSITION is one of `top', `middle', or `bottom', selecting the corner
+and junction characters (┌┬┐ / ├┼┤ / └┴┘).  Each column contributes
+`column-width' + 2 horizontal bars to match the one-space cell padding
+used by `pi-coding-agent--render-table-row-lines'."
+  (let ((left  (pcase position ('top "┌") ('bottom "└") (_ "├")))
+        (mid   (pcase position ('top "┬") ('bottom "┴") (_ "┼")))
+        (right (pcase position ('top "┐") ('bottom "┘") (_ "┤"))))
+    (concat left
+            (mapconcat (lambda (w) (make-string (+ w 2) ?─))
+                       col-widths mid)
+            right)))
 
 (defun pi-coding-agent--table-alignments (separator-line)
   "Return column alignment symbols parsed from SEPARATOR-LINE."
@@ -443,20 +474,53 @@ Plain tables (no prefix) take a fast path that skips prefix splitting."
               (mapcar (lambda (row)
                         (pi-coding-agent--render-table-row-lines
                          row col-widths aligns))
-                      display-rows)))
+                      display-rows))
+             ;; Full web-style grid: weave border rules into the existing
+             ;; per-raw-line groups so the group↔raw-line 1:1 invariant that
+             ;; `pi-coding-agent--decorate-table' relies on is preserved.
+             ;; The top border joins the header group, an inter-row rule
+             ;; prefixes every data group after the first, and the bottom
+             ;; border joins the last group (or the separator group when the
+             ;; table has no data rows).
+             (full-grid (pi-coding-agent--table-full-grid-p))
+             (has-data (consp row-groups))
+             (header-group
+              (if full-grid
+                  (cons (pi-coding-agent--render-table-grid-rule col-widths 'top)
+                        header-lines)
+                header-lines))
+             (sep-group
+              (if (and full-grid (not has-data))
+                  (list separator-line
+                        (pi-coding-agent--render-table-grid-rule col-widths 'bottom))
+                (list separator-line)))
+             (data-groups
+              (if (and full-grid has-data)
+                  (let ((mid-rule (pi-coding-agent--render-table-grid-rule
+                                   col-widths 'middle))
+                        (bottom (pi-coding-agent--render-table-grid-rule
+                                 col-widths 'bottom))
+                        (last-index (1- (length row-groups))))
+                    (cl-loop for group in row-groups
+                             for i from 0
+                             collect (append (when (> i 0) (list mid-rule))
+                                             group
+                                             (when (= i last-index) (list bottom)))))
+                row-groups)))
         (if no-prefix
-            (append (list header-lines)
-                    (list (list separator-line))
-                    row-groups)
+            (append (list header-group)
+                    (list sep-group)
+                    data-groups)
           (append
            (list (mapcar (lambda (line) (concat (car prefixes) line))
-                         header-lines))
-           (list (list (concat (nth 1 prefixes) separator-line)))
+                         header-group))
+           (list (mapcar (lambda (line) (concat (nth 1 prefixes) line))
+                         sep-group))
            (cl-mapcar (lambda (prefix row-lines)
                         (mapcar (lambda (line) (concat prefix line))
                                 row-lines))
                       (nthcdr 2 prefixes)
-                      row-groups)))))))
+                      data-groups)))))))
 
 ;;;; Line Mapping
 
diff --git a/pi-coding-agent-ui.el b/pi-coding-agent-ui.el
index 8e438e2..b0c49f1 100644
--- a/pi-coding-agent-ui.el
+++ b/pi-coding-agent-ui.el
@@ -285,6 +285,17 @@ still operate on the raw table source."
   :type 'boolean
   :group 'pi-coding-agent)
 
+(defcustom pi-coding-agent-table-full-grid t
+  "Whether prettified tables draw a full cell grid (web-style borders).
+When non-nil, and `pi-coding-agent-prettify-tables' is also enabled,
+tables render a top border, a horizontal rule between every row, and a
+bottom border using Unicode box-drawing characters, so each cell is fully
+enclosed like an HTML table.  When nil, tables keep only the column
+verticals and a single header rule.  Has no effect when
+`pi-coding-agent-prettify-tables' is nil (raw markdown pipes are used)."
+  :type 'boolean
+  :group 'pi-coding-agent)
+
 ;;;; Faces
 
 (defface pi-coding-agent-timestamp
diff --git a/test/pi-coding-agent-input-test.el b/test/pi-coding-agent-input-test.el
index 5f23da0..39d798e 100644
--- a/test/pi-coding-agent-input-test.el
+++ b/test/pi-coding-agent-input-test.el
@@ -53,6 +53,34 @@
           (pi-coding-agent-send)
           (should-not send-called))))))
 
+(ert-deftest pi-coding-agent-test-send-without-chat-preserves-input ()
+  "Sending from an unlinked input buffer preserves the draft and history."
+  (with-temp-buffer
+    (pi-coding-agent-input-mode)
+    (insert "unsent draft")
+    (let ((shown-message nil))
+      (cl-letf (((symbol-function 'message)
+                 (lambda (fmt &rest args)
+                   (setq shown-message (apply #'format fmt args)))))
+        (pi-coding-agent-send))
+      (should (equal (buffer-string) "unsent draft"))
+      (should (null pi-coding-agent--input-ring))
+      (should (equal shown-message "Pi: No chat session available")))))
+
+(ert-deftest pi-coding-agent-test-send-with-dead-chat-preserves-input ()
+  "Sending with a dead chat link preserves the draft without signaling."
+  (let ((dead-chat (generate-new-buffer
+                    "*pi-coding-agent-test-dead-send-chat*")))
+    (kill-buffer dead-chat)
+    (with-temp-buffer
+      (pi-coding-agent-input-mode)
+      (setq pi-coding-agent--chat-buffer dead-chat)
+      (insert "draft for dead chat")
+      (cl-letf (((symbol-function 'message) #'ignore))
+        (pi-coding-agent-send))
+      (should (equal (buffer-string) "draft for dead chat"))
+      (should (null pi-coding-agent--input-ring)))))
+
 (ert-deftest pi-coding-agent-test-send-queues-locally-while-streaming ()
   "pi-coding-agent-send adds to local queue while streaming, no RPC sent."
   (let ((chat-buf (get-buffer-create "*pi-coding-agent-test-queue-stream*"))
@@ -784,6 +812,41 @@ Uses :false (JSON false representation) to verify boolean normalization."
         (should (equal (plist-get sent-command :type) "abort"))
         (should-not pi-coding-agent--aborted)))))
 
+(ert-deftest pi-coding-agent-test-abort-sends-command-while-sending ()
+  "pi-coding-agent-abort sends abort while waiting for agent_start."
+  (with-temp-buffer
+    (pi-coding-agent-chat-mode)
+    (let ((sent-command nil)
+          (pi-coding-agent--status 'sending))
+      (cl-letf (((symbol-function 'pi-coding-agent--get-process)
+                 (lambda () 'mock-proc))
+                ((symbol-function 'pi-coding-agent--get-chat-buffer)
+                 (lambda () (current-buffer)))
+                ((symbol-function 'pi-coding-agent--rpc-async)
+                 (lambda (_proc command _callback)
+                   (setq sent-command command))))
+        (pi-coding-agent-abort)
+        (should (equal (plist-get sent-command :type) "abort"))
+        (should-not pi-coding-agent--aborted)))))
+
+(ert-deftest pi-coding-agent-test-abort-sends-command-during-auto-retry ()
+  "pi-coding-agent-abort cancels an auto-retry wait represented by sending."
+  (with-temp-buffer
+    (pi-coding-agent-chat-mode)
+    (let ((sent-command nil))
+      (pi-coding-agent--update-state-from-event
+       '(:type "auto_retry_start" :attempt 2 :errorMessage "retrying"))
+      (should (eq pi-coding-agent--status 'sending))
+      (cl-letf (((symbol-function 'pi-coding-agent--get-process)
+                 (lambda () 'mock-proc))
+                ((symbol-function 'pi-coding-agent--get-chat-buffer)
+                 (lambda () (current-buffer)))
+                ((symbol-function 'pi-coding-agent--rpc-async)
+                 (lambda (_proc command _callback)
+                   (setq sent-command command))))
+        (pi-coding-agent-abort)
+        (should (equal (plist-get sent-command :type) "abort"))))))
+
 (ert-deftest pi-coding-agent-test-abort-noop-when-idle ()
   "pi-coding-agent-abort does nothing when idle."
   (with-temp-buffer
@@ -2864,6 +2927,29 @@ only offer our own capfs (slash commands, file references, paths)."
       ;; No duplicates
       (should (= (length (seq-filter (lambda (n) (equal n "compact")) names)) 1)))))
 
+(ert-deftest pi-coding-agent-test-command-capf-ignores-arguments ()
+  "Command completion does not treat arguments as part of the command name."
+  (with-temp-buffer
+    (pi-coding-agent-input-mode)
+    (insert "/compact keep these details")
+    (let ((before (buffer-string)))
+      (should-not (pi-coding-agent--command-capf))
+      (should (equal (buffer-string) before)))))
+
+(ert-deftest pi-coding-agent-test-command-capf-region-stops-before-arguments ()
+  "Command completion replaces only the command token before arguments."
+  (with-temp-buffer
+    (pi-coding-agent-input-mode)
+    (insert "/comp keep details")
+    (goto-char 6)
+    (let ((completion (pi-coding-agent--command-capf)))
+      (should completion)
+      (should (= (nth 0 completion) 2))
+      (should (= (nth 1 completion) 6))
+      (should (equal (buffer-substring-no-properties
+                      (nth 1 completion) (point-max))
+                     " keep details")))))
+
 (ert-deftest pi-coding-agent-test-send-prompt-sends-literal ()
   "pi-coding-agent--send-prompt sends text literally (no expansion).
 Pi handles command expansion on the server side."
@@ -3955,6 +4041,40 @@ This occurs after compaction before the next assistant message."
       (should result)
       (should (member "test.el" (nth 2 result))))))
 
+(ert-deftest pi-coding-agent-test-file-reference-capf-basic-prefix-match ()
+  "Basic completion matches the project-relative path prefix."
+  (with-temp-buffer
+    (pi-coding-agent-input-mode)
+    (setq pi-coding-agent--project-files-cache
+          '("dir/foo.el" "other/bar.el")
+          pi-coding-agent--project-files-cache-time (float-time))
+    (insert "@dir/f")
+    (let* ((completion-styles '(basic))
+           (capf (pi-coding-agent--file-reference-capf))
+           (input (buffer-substring-no-properties
+                   (nth 0 capf) (nth 1 capf)))
+           (matches (completion-all-completions
+                     input (nth 2 capf) nil (length input))))
+      (should (equal (substring-no-properties (car matches))
+                     "dir/foo.el")))))
+
+(ert-deftest pi-coding-agent-test-file-reference-capf-flex-controls-matching ()
+  "Flex completion can match candidates not selected by literal substring."
+  (with-temp-buffer
+    (pi-coding-agent-input-mode)
+    (setq pi-coding-agent--project-files-cache
+          '("dir/foo.el" "other/bar.el")
+          pi-coding-agent--project-files-cache-time (float-time))
+    (insert "@dfe")
+    (let* ((completion-styles '(flex))
+           (capf (pi-coding-agent--file-reference-capf))
+           (input (buffer-substring-no-properties
+                   (nth 0 capf) (nth 1 capf)))
+           (matches (completion-all-completions
+                     input (nth 2 capf) nil (length input))))
+      (should (equal (substring-no-properties (car matches))
+                     "dir/foo.el")))))
+
 ;;; Path Completion (Tab)
 
 (ert-deftest pi-coding-agent-test-path-capf-returns-nil-for-non-path ()
diff --git a/test/pi-coding-agent-menu-test.el b/test/pi-coding-agent-menu-test.el
index 5e4d8ad..9bfe759 100644
--- a/test/pi-coding-agent-menu-test.el
+++ b/test/pi-coding-agent-menu-test.el
@@ -644,6 +644,88 @@ BINDING-SPEC is (DIR CHAT-NAME INPUT-NAME PROC).  DIR is evaluated once."
             (delete-process pi-coding-agent--process)))
         (kill-buffer chat-buf)))))
 
+(ert-deftest pi-coding-agent-test-reload-refuses-while-transition-active ()
+  "Reload does not start another process during an active session transition."
+  (let ((start-count 0)
+        (shown-message nil)
+        (chat-buf (generate-new-buffer
+                   "*pi-coding-agent-test-reload-reentry-chat*")))
+    (unwind-protect
+        (progn
+          (with-current-buffer chat-buf
+            (pi-coding-agent-chat-mode)
+            (setq pi-coding-agent--state
+                  '(:session-file "/tmp/test-session.json"))
+            (pi-coding-agent--begin-session-transition 'active-transition))
+          (cl-letf (((symbol-function 'pi-coding-agent--get-chat-buffer)
+                     (lambda () chat-buf))
+                    ((symbol-function 'pi-coding-agent--start-process)
+                     (lambda (_dir)
+                       (setq start-count (1+ start-count))
+                       (ert-fail "Reload must not start during a transition")))
+                    ((symbol-function 'message)
+                     (lambda (fmt &rest args)
+                       (setq shown-message (apply #'format fmt args)))))
+            (pi-coding-agent-reload))
+          (should (= start-count 0))
+          (should (equal shown-message
+                         "Pi: Cannot reload while Pi is busy")))
+      (when (buffer-live-p chat-buf)
+        (kill-buffer chat-buf)))))
+
+(ert-deftest pi-coding-agent-test-stale-reload-callback-cleans-new-process ()
+  "A stale reload callback releases the temporary process it owns."
+  (let ((old-proc nil)
+        (new-proc nil)
+        (new-stderr nil)
+        (switch-callback nil)
+        (chat-buf (generate-new-buffer
+                   "*pi-coding-agent-test-stale-reload-chat*")))
+    (unwind-protect
+        (progn
+          (with-current-buffer chat-buf
+            (pi-coding-agent-chat-mode)
+            (setq pi-coding-agent--state
+                  '(:session-file "/tmp/test-session.json"))
+            (setq old-proc (start-process "test-stale-reload-old" nil "cat")
+                  pi-coding-agent--process old-proc))
+          (cl-letf (((symbol-function 'pi-coding-agent--get-chat-buffer)
+                     (lambda () chat-buf))
+                    ((symbol-function 'pi-coding-agent--start-process)
+                     (lambda (_dir)
+                       (setq new-proc
+                             (start-process "test-stale-reload-new" nil "cat")
+                             new-stderr
+                             (generate-new-buffer
+                              " *pi-coding-agent-test-stale-stderr*"))
+                       (process-put new-proc
+                                    'pi-coding-agent-stderr-buf new-stderr)
+                       new-proc))
+                    ((symbol-function 'pi-coding-agent--rpc-async)
+                     (lambda (_proc command callback)
+                       (when (equal (plist-get command :type) "switch_session")
+                         (setq switch-callback callback))))
+                    ((symbol-function 'message) #'ignore))
+            (pi-coding-agent-reload))
+          (should (functionp switch-callback))
+          (should (process-live-p new-proc))
+          (should (process-get new-proc 'pi-coding-agent-display-handler))
+          (with-current-buffer chat-buf
+            (pi-coding-agent--begin-session-transition 'replacement-process))
+          (funcall switch-callback
+                   '(:success t :data (:cancelled :false)))
+          (should-not (process-live-p new-proc))
+          (should-not
+           (process-get new-proc 'pi-coding-agent-display-handler))
+          (should-not (buffer-live-p new-stderr))
+          (should (process-live-p old-proc)))
+      (when (and old-proc (process-live-p old-proc))
+        (delete-process old-proc))
+      (when (and new-proc (process-live-p new-proc))
+        (delete-process new-proc))
+      (when (buffer-live-p chat-buf)
+        (kill-buffer chat-buf)))))
+
 (ert-deftest pi-coding-agent-test-reload-switch-failure-keeps-old-process ()
   "A failed reload switch does not attach the fresh process to the UI."
   (let* ((old-proc nil)
diff --git a/test/pi-coding-agent-render-test.el b/test/pi-coding-agent-render-test.el
index 0d714d5..5830f9c 100644
--- a/test/pi-coding-agent-render-test.el
+++ b/test/pi-coding-agent-render-test.el
@@ -88,6 +88,30 @@
       (should (= table-scan-count 1))
       (should-not pi-coding-agent--streaming-table-candidate))))
 
+(ert-deftest pi-coding-agent-test-assistant-message-start-resets-line-state ()
+  "A later assistant message starts at a fresh Markdown line."
+  (with-temp-buffer
+    (pi-coding-agent-chat-mode)
+    (setq pi-coding-agent--line-parse-state 'mid-line
+          pi-coding-agent--assistant-header-shown t)
+    (pi-coding-agent--handle-display-event
+     '(:type "message_start" :message (:role "assistant")))
+    (should (eq pi-coding-agent--line-parse-state 'line-start))
+    (should (equal (pi-coding-agent--transform-delta "# Heading")
+                   "## Heading"))))
+
+(ert-deftest pi-coding-agent-test-assistant-message-start-resets-block-state ()
+  "A later assistant message does not inherit code or table parse state."
+  (with-temp-buffer
+    (pi-coding-agent-chat-mode)
+    (setq pi-coding-agent--in-code-block t
+          pi-coding-agent--streaming-table-candidate '(10 . 20)
+          pi-coding-agent--assistant-header-shown t)
+    (pi-coding-agent--handle-display-event
+     '(:type "message_start" :message (:role "assistant")))
+    (should-not pi-coding-agent--in-code-block)
+    (should-not pi-coding-agent--streaming-table-candidate)))
+
 (ert-deftest pi-coding-agent-test-delta-transforms-atx-headings ()
   "ATX headings in assistant content are leveled down.
 # becomes ##, ## becomes ###, etc. This keeps our setext H1 separators
diff --git a/test/pi-coding-agent-table-test.el b/test/pi-coding-agent-table-test.el
index 42e2d36..2c4b7ae 100644
--- a/test/pi-coding-agent-table-test.el
+++ b/test/pi-coding-agent-table-test.el
@@ -409,6 +409,33 @@ so visible text still needs consistent alignment across all display lines."
       (let ((widths (mapcar #'string-width (nreverse all-lines))))
         (should (= (length (delete-dups (copy-sequence widths))) 1))))))
 
+(ert-deftest pi-coding-agent-test-zero-width-column-keeps-separator-aligned ()
+  "A zero-width column occupies the same width in rows and separators."
+  (dolist (pretty '(t nil))
+    (let* ((pi-coding-agent-prettify-tables pretty)
+           (widths '(1 0 2))
+           (aligns '(nil nil nil))
+           (row (car (pi-coding-agent--render-table-row-lines
+                      '("a" "" "bc") widths aligns)))
+           (separator (pi-coding-agent--render-table-separator-line
+                       widths aligns)))
+      (should (= (string-width row) (string-width separator))))))
+
+(ert-deftest pi-coding-agent-test-short-alignments-render-all-columns ()
+  "Missing alignment entries default without truncating trailing columns."
+  (dolist (pretty '(t nil))
+    (let* ((pi-coding-agent-prettify-tables pretty)
+           (widths '(1 1 1))
+           (aligns '(left))
+           (row (car (pi-coding-agent--render-table-row-lines
+                      '("a" "b" "c") widths aligns)))
+           (separator (pi-coding-agent--render-table-separator-line
+                       widths aligns)))
+      (should (string-match-p "a" row))
+      (should (string-match-p "b" row))
+      (should (string-match-p "c" row))
+      (should (= (string-width row) (string-width separator))))))
+
 (ert-deftest pi-coding-agent-test-decorate-table-prettifies-visible-separators ()
   "Rendered table display uses box-drawing separators instead of raw pipes."
   (with-temp-buffer
@@ -430,6 +457,78 @@ so visible text still needs consistent alignment across all display lines."
       (should (string-match-p "Name" all-display))
       (should (string-match-p "Alpha" all-display)))))
 
+(ert-deftest pi-coding-agent-test-render-table-grid-rule-widths-match-rows ()
+  "Top, middle, and bottom grid rules share the width of pretty data rows."
+  (let* ((pi-coding-agent-prettify-tables t)
+         (widths '(5 1 0 3))
+         (aligns '(nil nil nil nil))
+         (row (car (pi-coding-agent--render-table-row-lines
+                    '("a" "b" "" "d") widths aligns)))
+         (top (pi-coding-agent--render-table-grid-rule widths 'top))
+         (mid (pi-coding-agent--render-table-grid-rule widths 'middle))
+         (bot (pi-coding-agent--render-table-grid-rule widths 'bottom)))
+    (should (string-prefix-p "┌" top))
+    (should (string-suffix-p "┐" top))
+    (should (string-match-p "┬" top))
+    (should (string-prefix-p "├" mid))
+    (should (string-suffix-p "┤" mid))
+    (should (string-match-p "┼" mid))
+    (should (string-prefix-p "└" bot))
+    (should (string-suffix-p "┘" bot))
+    (should (string-match-p "┴" bot))
+    (should (= (string-width row) (string-width top)))
+    (should (= (string-width row) (string-width mid)))
+    (should (= (string-width row) (string-width bot)))))
+
+(ert-deftest pi-coding-agent-test-decorate-table-full-grid-encloses-cells ()
+  "With full grid enabled, a decorated table gains top/mid/bottom borders."
+  (with-temp-buffer
+    (pi-coding-agent-chat-mode)
+    (let ((pi-coding-agent-prettify-tables t)
+          (pi-coding-agent-table-full-grid t)
+          (inhibit-read-only t))
+      (insert "| Name | Value |\n|------|-------|\n| Alpha | Beta |\n| Gamma | Delta |\n")
+      (font-lock-ensure)
+      (pi-coding-agent--decorate-tables-in-region (point-min) (point-max) 40)
+      (let* ((displays (pi-coding-agent-test--table-overlay-displays-in-region
+                        (point-min) (point-max)))
+             (all (mapconcat #'identity displays "\n"))
+             ;; Split each overlay individually to avoid empty lines from the
+             ;; trailing newlines already present in each display string.
+             (lines nil))
+        (dolist (display displays)
+          (dolist (line (split-string
+                         (string-trim-right display "\n+") "\n"))
+            (push line lines)))
+        ;; Top border, an inter-row rule, and a bottom border are present.
+        (should (string-match-p "┌.*┬.*┐" all))
+        (should (string-match-p "├.*┼.*┤" all))
+        (should (string-match-p "└.*┴.*┘" all))
+        ;; Every visible line has the same display width (full alignment).
+        (should (= (length (delete-dups
+                            (mapcar #'string-width lines)))
+                   1))
+        ;; The 1:1 group↔raw-line invariant: one overlay per raw line (4).
+        (should (= (length displays) 4))))))
+
+(ert-deftest pi-coding-agent-test-decorate-table-full-grid-off-has-no-outer-border ()
+  "With full grid disabled, only header rule remains (no top/bottom border)."
+  (with-temp-buffer
+    (pi-coding-agent-chat-mode)
+    (let ((pi-coding-agent-prettify-tables t)
+          (pi-coding-agent-table-full-grid nil)
+          (inhibit-read-only t))
+      (insert "| Name | Value |\n|------|-------|\n| Alpha | Beta |\n")
+      (font-lock-ensure)
+      (pi-coding-agent--decorate-tables-in-region (point-min) (point-max) 40)
+      (let ((all (mapconcat #'identity
+                            (pi-coding-agent-test--table-overlay-displays-in-region
+                             (point-min) (point-max))
+                            "\n")))
+        (should (string-match-p "├.*┼.*┤" all))
+        (should-not (string-match-p "┌" all))
+        (should-not (string-match-p "└" all))))))
+
 (ert-deftest pi-coding-agent-test-decorate-table-preserves-pipes-when-prettify-off ()
   "With prettify disabled, rendered tables use standard markdown pipes."
   (with-temp-buffer