diff --git a/canvas/src/components/tabs/ConfigTab.tsx b/canvas/src/components/tabs/ConfigTab.tsx
index 09742689..9ef1f0d4 100644
--- a/canvas/src/components/tabs/ConfigTab.tsx
+++ b/canvas/src/components/tabs/ConfigTab.tsx
@@ -51,17 +51,18 @@ function AgentCardSection({ workspaceId }: { workspaceId: string }) {
       ) : editing ? (
         <div className="space-y-2">
           <textarea
+            aria-label="Agent card JSON editor"
             value={draft} onChange={(e) => setDraft(e.target.value)}
             spellCheck={false} rows={12}
             className="w-full bg-zinc-800 border border-zinc-700 rounded p-2 text-[10px] font-mono text-zinc-200 focus:outline-none focus:border-blue-500 resize-none"
           />
           {error && <div className="px-2 py-1 bg-red-900/30 border border-red-800 rounded text-[10px] text-red-400">{error}</div>}
           <div className="flex gap-2">
-            <button onClick={handleSave} disabled={saving}
+            <button type="button" onClick={handleSave} disabled={saving}
               className="px-2 py-1 bg-blue-600 hover:bg-blue-500 text-[10px] rounded text-white disabled:opacity-50">
               {saving ? "Saving..." : "Save"}
             </button>
-            <button onClick={() => setEditing(false)}
+            <button type="button" onClick={() => setEditing(false)}
               className="px-2 py-1 bg-zinc-700 hover:bg-zinc-600 text-[10px] rounded text-zinc-300">Cancel</button>
           </div>
         </div>
@@ -75,7 +76,7 @@ function AgentCardSection({ workspaceId }: { workspaceId: string }) {
             <div className="text-[10px] text-zinc-500">No agent card</div>
           )}
           {success && <div className="mt-2 px-2 py-1 bg-green-900/30 border border-green-800 rounded text-[10px] text-green-400">Updated</div>}
-          <button onClick={() => { setDraft(JSON.stringify(card || {}, null, 2)); setEditing(true); setError(null); setSuccess(false); }}
+          <button type="button" onClick={() => { setDraft(JSON.stringify(card || {}, null, 2)); setEditing(true); setError(null); setSuccess(false); }}
             className="mt-2 text-[10px] text-blue-400 hover:text-blue-300">Edit Agent Card</button>
         </div>
       )}
@@ -372,6 +373,7 @@ export function ConfigTab({ workspaceId }: Props) {
       {rawMode ? (
         <div className="flex-1 p-3">
           <textarea
+            aria-label="Raw YAML editor"
             value={rawDraft}
             onChange={(e) => setRawDraft(e.target.value)}
             spellCheck={false}
@@ -633,6 +635,7 @@ export function ConfigTab({ workspaceId }: Props) {
 
       <div className="p-3 border-t border-zinc-800 flex gap-2">
         <button
+          type="button"
           onClick={() => handleSave(true)}
           disabled={!isDirty || saving}
           className="px-3 py-1.5 bg-blue-600 hover:bg-blue-500 text-xs rounded text-white disabled:opacity-30 transition-colors"
@@ -640,6 +643,7 @@ export function ConfigTab({ workspaceId }: Props) {
           {saving ? "Restarting..." : "Save & Restart"}
         </button>
         <button
+          type="button"
           onClick={() => handleSave(false)}
           disabled={!isDirty || saving}
           className="px-3 py-1.5 bg-zinc-700 hover:bg-zinc-600 text-xs rounded text-zinc-300 disabled:opacity-30 transition-colors"
@@ -647,6 +651,7 @@ export function ConfigTab({ workspaceId }: Props) {
           Save
         </button>
         <button
+          type="button"
           onClick={loadConfig}
           className="px-3 py-1.5 bg-zinc-700 hover:bg-zinc-600 text-xs rounded text-zinc-300 ml-auto"
         >
diff --git a/canvas/src/components/tabs/DetailsTab.tsx b/canvas/src/components/tabs/DetailsTab.tsx
index 5d877cf9..8bd0d69a 100644
--- a/canvas/src/components/tabs/DetailsTab.tsx
+++ b/canvas/src/components/tabs/DetailsTab.tsx
@@ -159,6 +159,7 @@ export function DetailsTab({ workspaceId, data }: Props) {
             )}
             <div className="flex gap-2 pt-1">
               <button
+                type="button"
                 onClick={handleSave}
                 disabled={saving}
                 className="px-3 py-1 bg-blue-600 hover:bg-blue-500 text-xs rounded text-white disabled:opacity-50"
@@ -166,6 +167,7 @@ export function DetailsTab({ workspaceId, data }: Props) {
                 {saving ? "Saving..." : "Save"}
               </button>
               <button
+                type="button"
                 onClick={() => {
                   setEditing(false);
                   setSaveError(null);
@@ -199,6 +201,7 @@ export function DetailsTab({ workspaceId, data }: Props) {
                   </div>
                 )}
                 <button
+                  type="button"
                   onClick={handleRestart}
                   disabled={restarting}
                   className="px-3 py-1 bg-green-700 hover:bg-green-600 text-xs rounded text-white disabled:opacity-50"
@@ -208,6 +211,7 @@ export function DetailsTab({ workspaceId, data }: Props) {
               </div>
             )}
             <button
+              type="button"
               onClick={() => setEditing(true)}
               className="mt-2 px-3 py-1 bg-zinc-700 hover:bg-zinc-600 text-xs rounded text-zinc-300"
             >
@@ -234,6 +238,7 @@ export function DetailsTab({ workspaceId, data }: Props) {
             <p className="text-xs text-zinc-500">No error detail recorded.</p>
           )}
           <button
+            type="button"
             onClick={() => setConsoleOpen(true)}
             className="mt-2 px-3 py-1 bg-zinc-800 hover:bg-zinc-700 text-xs rounded text-zinc-300 border border-zinc-700"
           >
@@ -279,6 +284,7 @@ export function DetailsTab({ workspaceId, data }: Props) {
             {peers.map((p) => (
               <button
                 key={p.id}
+                type="button"
                 onClick={() => selectNode(p.id)}
                 className="w-full flex items-center gap-2 px-2 py-1 rounded hover:bg-zinc-800 text-left"
               >
@@ -310,12 +316,14 @@ export function DetailsTab({ workspaceId, data }: Props) {
             </h3>
             <div className="flex gap-2">
               <button
+                type="button"
                 onClick={handleDelete}
                 className="px-3 py-1 bg-red-600 hover:bg-red-500 text-xs rounded text-white"
               >
                 Confirm Delete
               </button>
               <button
+                type="button"
                 onClick={() => {
                   setConfirmDelete(false);
                   setDeleteError(null);
@@ -330,6 +338,7 @@ export function DetailsTab({ workspaceId, data }: Props) {
           </div>
         ) : (
           <button
+            type="button"
             ref={deleteButtonRef}
             onClick={() => setConfirmDelete(true)}
             className="px-3 py-1 bg-zinc-800 hover:bg-red-900 border border-zinc-700 hover:border-red-700 text-xs rounded text-zinc-400 hover:text-red-400 transition-colors"
diff --git a/canvas/src/components/tabs/FilesTab.tsx b/canvas/src/components/tabs/FilesTab.tsx
index de771087..4b50bfc3 100644
--- a/canvas/src/components/tabs/FilesTab.tsx
+++ b/canvas/src/components/tabs/FilesTab.tsx
@@ -165,8 +165,8 @@ export function FilesTab({ workspaceId }: Props) {
         <div className="mx-3 mt-2 px-3 py-2 bg-red-950/30 border border-red-800/40 rounded space-y-1.5">
           <p className="text-xs text-red-300">Delete all {files.filter((f) => !f.dir).length} files? This cannot be undone.</p>
           <div className="flex gap-2">
-            <button onClick={() => { handleDeleteAll(); setShowDeleteAll(false); }} className="px-2 py-0.5 bg-red-600 hover:bg-red-500 text-[10px] rounded text-white">Delete All</button>
-            <button onClick={() => setShowDeleteAll(false)} className="px-2 py-0.5 bg-zinc-700 hover:bg-zinc-600 text-[10px] rounded text-zinc-300">Cancel</button>
+            <button type="button" onClick={() => { handleDeleteAll(); setShowDeleteAll(false); }} className="px-2 py-0.5 bg-red-600 hover:bg-red-500 text-[10px] rounded text-white">Delete All</button>
+            <button type="button" onClick={() => setShowDeleteAll(false)} className="px-2 py-0.5 bg-zinc-700 hover:bg-zinc-600 text-[10px] rounded text-zinc-300">Cancel</button>
           </div>
         </div>
       )}
@@ -179,8 +179,8 @@ export function FilesTab({ workspaceId }: Props) {
         <div className="mx-3 mt-2 px-3 py-2 bg-amber-950/30 border border-amber-800/40 rounded space-y-1.5">
           <p className="text-xs text-amber-300">Delete <span className="font-mono">{confirmDelete}</span>{files.find((f) => f.path === confirmDelete && f.dir) ? " and all its contents" : ""}?</p>
           <div className="flex gap-2">
-            <button onClick={confirmDeleteFile} className="px-2 py-0.5 bg-red-600 hover:bg-red-500 text-[10px] rounded text-white">Delete</button>
-            <button onClick={() => setConfirmDelete(null)} className="px-2 py-0.5 bg-zinc-700 hover:bg-zinc-600 text-[10px] rounded text-zinc-300">Cancel</button>
+            <button type="button" onClick={confirmDeleteFile} className="px-2 py-0.5 bg-red-600 hover:bg-red-500 text-[10px] rounded text-white">Delete</button>
+            <button type="button" onClick={() => setConfirmDelete(null)} className="px-2 py-0.5 bg-zinc-700 hover:bg-zinc-600 text-[10px] rounded text-zinc-300">Cancel</button>
           </div>
         </div>
       )}
diff --git a/canvas/src/components/tabs/MemoryTab.tsx b/canvas/src/components/tabs/MemoryTab.tsx
index 721e0d8a..46ce352b 100644
--- a/canvas/src/components/tabs/MemoryTab.tsx
+++ b/canvas/src/components/tabs/MemoryTab.tsx
@@ -135,12 +135,14 @@ export function MemoryTab({ workspaceId }: Props) {
           </div>
           <div className="flex items-center gap-2">
             <button
+              type="button"
               onClick={() => setShowAwareness((prev) => !prev)}
               className="shrink-0 px-2 py-1 bg-zinc-700 hover:bg-zinc-600 text-[10px] rounded text-zinc-200"
             >
               {showAwareness ? "Collapse" : "Expand"}
             </button>
             <button
+              type="button"
               onClick={openAwareness}
               className="shrink-0 px-2 py-1 bg-zinc-700 hover:bg-zinc-600 text-[10px] rounded text-zinc-200"
             >
@@ -173,6 +175,7 @@ export function MemoryTab({ workspaceId }: Props) {
               </p>
             </div>
             <button
+              type="button"
               onClick={() => setShowAwareness(true)}
               className="shrink-0 px-2 py-1 bg-blue-600 hover:bg-blue-500 text-[10px] rounded text-white"
             >
@@ -207,18 +210,21 @@ export function MemoryTab({ workspaceId }: Props) {
           </div>
           <div className="flex gap-2">
             <button
+              type="button"
               onClick={() => setShowAdvanced((prev) => !prev)}
               className="px-2 py-1 bg-zinc-700 hover:bg-zinc-600 text-[10px] rounded text-zinc-300"
             >
               {showAdvanced ? "Hide Advanced" : "Advanced"}
             </button>
             <button
+              type="button"
               onClick={loadMemory}
               className="px-2 py-1 bg-zinc-700 hover:bg-zinc-600 text-[10px] rounded text-zinc-300"
             >
               Refresh
             </button>
             <button
+              type="button"
               onClick={() => { setShowAdd(!showAdd); if (!showAdd) setShowAdvanced(true); }}
               className="px-2 py-1 bg-blue-600 hover:bg-blue-500 text-[10px] rounded text-white"
             >
@@ -254,12 +260,14 @@ export function MemoryTab({ workspaceId }: Props) {
             {error && <div role="alert" className="text-xs text-red-400">{error}</div>}
             <div className="flex gap-2">
               <button
+                type="button"
                 onClick={handleAdd}
                 className="px-3 py-1 bg-blue-600 hover:bg-blue-500 text-xs rounded text-white"
               >
                 Save
               </button>
               <button
+                type="button"
                 onClick={() => {
                   setShowAdd(false);
                   setError(null);
@@ -280,6 +288,7 @@ export function MemoryTab({ workspaceId }: Props) {
               {entries.map((entry) => (
                 <div key={entry.key} className="bg-zinc-800 rounded border border-zinc-700">
                   <button
+                    type="button"
                     onClick={() => setExpanded(expanded === entry.key ? null : entry.key)}
                     className="w-full flex items-center justify-between px-3 py-2 text-left"
                     aria-expanded={expanded === entry.key}
@@ -307,6 +316,7 @@ export function MemoryTab({ workspaceId }: Props) {
                           Updated: {new Date(entry.updated_at).toLocaleString()}
                         </span>
                         <button
+                          type="button"
                           onClick={() => handleDelete(entry.key)}
                           className="text-[10px] text-red-400 hover:text-red-300"
                         >
@@ -328,6 +338,7 @@ export function MemoryTab({ workspaceId }: Props) {
               </p>
             </div>
             <button
+              type="button"
               onClick={() => setShowAdvanced(true)}
               className="shrink-0 px-2 py-1 bg-blue-600 hover:bg-blue-500 text-[10px] rounded text-white"
             >