diff --git a/CHANGELOG.md b/CHANGELOG.md
index abf5aa7..61bbf8e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,26 @@ All notable changes to this project are documented here.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Fixed
+
+- **The main pane no longer scrolls sideways.** 0.3.3 stopped the *window*
+  sliding as one sheet but left the board scrolling in both axes, so reaching
+  the last client column of the MCP matrix dragged the view's title, its notes
+  and its "Config paths" list off to the left with it — everything you needed
+  as a reference left the screen at the moment you needed it. The board now
+  scrolls down only; the tables scroll inside their own frame, which is what
+  that frame was always for. Errors wrap instead of running off the edge, since
+  a clipped error is worse than a wide one.
+
+  The MCP table also stopped asking for width it never used: its floor was
+  760px against the 686px of pane a 900px window gives, so the matrix scrolled
+  even when it would have fitted. Six client columns of one glyph each carried
+  10px of side padding around nothing; at 7px, and with the floor at 640px —
+  the same as the vault's, and above the ~613px the headers themselves need —
+  a typical matrix comes to 666px and fits the smallest window with room over.
+
 ## [0.3.3] - 2026-08-14
 
 ### Fixed
diff --git a/app/src/App.tsx b/app/src/App.tsx
index fd67b9c..bd6f3d1 100644
--- a/app/src/App.tsx
+++ b/app/src/App.tsx
@@ -204,7 +204,10 @@ export default function App() {
           {view === "mcp" && <McpView />}
 
           {view === "board" && (
-            <>
+            /* Same wrapper the other two views use: one idiom for "a view",
+               and `min-width: 0` on it is what keeps a wide child scrolling
+               inside its own frame rather than pushing the pane. */
+            <div className="view">
               {error && (
                 <div className="banner">
                   <span className="glyph">△</span>
@@ -234,7 +237,7 @@ export default function App() {
                   ))}
                 </div>
               )}
-            </>
+            </div>
           )}
         </main>
       </div>
diff --git a/app/src/styles.css b/app/src/styles.css
index 6d41bd1..196975a 100644
--- a/app/src/styles.css
+++ b/app/src/styles.css
@@ -190,7 +190,9 @@ button {
    is content-driven even where its items may shrink, so one wide card row or
    one long unbroken path in a note sized this column past the window and took
    the whole document scrolling sideways with it. `overflow: hidden` then makes
-   the containment structural rather than a thing each child remembers. */
+   the containment structural rather than a thing each child remembers. The
+   board below carries the same rule one level in: it may scroll down, never
+   sideways. */
 .body {
   display: flex;
   min-width: 0;
@@ -198,11 +200,17 @@ button {
   overflow: hidden;
 }
 
+/* Down, never sideways. Reading a view is a vertical act; dragging the pane
+   right to reach the last column of a table would take the view's title, its
+   notes and its config paths along for the ride and leave nothing anchored.
+   So the one thing here that is genuinely wider than the pane — a table —
+   scrolls inside its own `.scroller`, and everything else wraps or clips. */
 .board {
   flex: 1 1 auto;
   min-width: 0;
   min-height: 0;
-  overflow: auto;
+  overflow-y: auto;
+  overflow-x: hidden;
   padding: 16px 18px 22px;
 }
 
@@ -404,6 +412,11 @@ button {
   margin: 24px 2px;
 }
 
+/* `overflow-wrap: anywhere` for the same reason `.notes li` has it, and now
+   load-bearing: an error string is whatever a CLI handed back, and one
+   unbroken token — a path, a key id — used to size this row past the pane and
+   scroll it. The pane no longer scrolls sideways, so an unbroken token would
+   simply be lost instead. Break it. */
 .banner {
   display: flex;
   gap: 8px;
@@ -414,6 +427,7 @@ button {
   background: var(--risk-wash);
   color: var(--ink);
   font-size: 12px;
+  overflow-wrap: anywhere;
 }
 
 /* A newer patchbay is news, not a fault: same row, accent instead of risk. */
@@ -1399,8 +1413,12 @@ dialog.detail {
   background: transparent;
 }
 
-/* Wide tables scroll inside their own frame; the pane never scrolls sideways. */
+/* Wide tables scroll inside their own frame; the pane never scrolls sideways.
+   `min-width: 0` because this is a flex item of `.view`: without it the box
+   would take its min-content width from the table and push past the pane
+   instead of scrolling, which is the whole thing it exists to prevent. */
 .scroller {
+  min-width: 0;
   overflow-x: auto;
   border: 1px solid var(--line);
   border-radius: 8px;
@@ -1445,8 +1463,14 @@ dialog.detail {
   min-width: 640px;
 }
 
+/* Same floor as the vault, and it is a floor rather than a target: the six
+   client headers alone need ~476px and "SERVER"/"TRANSPORT" another ~137, so
+   613px is the narrowest the matrix can be drawn at all. 640 leaves a little
+   slack without inventing width the table does not use — the old 760 padded it
+   past the 686px pane a 900px window gives, so the matrix scrolled sideways
+   even when it would have fitted. */
 .table-mcp {
-  min-width: 760px;
+  min-width: 640px;
 }
 
 .cell-id {
@@ -1482,6 +1506,18 @@ dialog.detail {
   text-align: center;
 }
 
+/* Six columns whose content is one glyph and whose width is set entirely by
+   the header label, so the side padding is space around nothing. Trimming it
+   to 7px buys 36px back across the row — enough that a typical matrix (666px)
+   fits the 686px pane a 900px window gives instead of scrolling. Qualified by
+   `.table` because `.table th`/`.table td` set the default padding and would
+   otherwise outrank a bare class. */
+.table th.col-client,
+.table td.cell-mark {
+  padding-left: 7px;
+  padding-right: 7px;
+}
+
 /* A client with no config file keeps its column: an empty column is the answer
    to "did I set it up there?", and hiding it would lose the answer. */
 .col-client.is-absent {