Tower spawns the process before checking the 100-session cap, so every rejected create leaks one #171

Open
Open
Tower spawns the process before checking the 100-session cap, so every rejected create leaks one#171
Labels
area/towerTower, afx, terminals, messaging

Description

@pseudoseed
pseudoseed
opened on Aug 29, 2026

Tower is wedged at its 100-session cap and cannot create terminals. Worse, each rejected attempt leaks the process it just spawned, so the condition amplifies itself the longer it lasts.

The leak

From ~/.agent-farm/tower.log:

[06:53:00.936] [INFO] Creating session 7c7ce4ed…: command=/bin/bash, socket=…
[06:53:01.088] [INFO] Session 7c7ce4ed… created: pid=22158
[06:53:01.089] [WARN] Shellper creation failed for terminal, falling back: Maximum 100 sessions reached
[06:53:01.089] [ERROR] Failed to create terminal: Maximum 100 sessions reached

The order is the bug. Tower spawns the process first, then checks the cap, then reports failure — and does not kill what it just started. pid=22158 is still running, parented to Tower (ppid 44799), long after the request that created it was reported as failed.

So every terminal request made while at the cap adds one more orphaned /bin/bash under a shellper. The fuller Tower gets, the faster it fills.

Not every leak is silent: a second attempt in the same second logged Session bbc6c8c4… exited (code=127). So some spawns do exit and some do not, which is why the leak looks intermittent rather than one-per-attempt.

Scale observed

  • 148Maximum 100 sessions reached entries since 2026-08-28T22:52:38Z, roughly 8 hours.
  • 157 live shellper processes holding about 2.4 GB.
  • 127 of them belong to a workspace with no active work in it, whose last real log entry is from Aug 16.
  • Process start times cluster in bursts matching the cap-hit bursts: 64 in one hour, 25 in the next.
  • 29 of the shellpers have been reparented to init (ppid 1), so Tower is no longer tracking them at all.

Two separate defects

  1. Spawn-then-check. Check the cap before spawning. If the check must stay where it is, kill the just-created session on the failure path before returning the error. A failed create must leave nothing behind.
  2. Nothing reaps dead sessions. Tower counts 100 sessions against a cap of 100 while the workspaces that own most of them have no live work. Whatever removes a session from the count is not running, or is not reached when a shellper dies unexpectedly. Reconcile the session table against live processes periodically, and on every cap rejection, so the cap reflects reality rather than accumulated bookkeeping.

Operator impact

This presents as "I cannot open a terminal" with no indication of why, in a workspace that is not the one at fault. The error surfaced to the caller is Failed to create terminal: Maximum 100 sessions reached, which names the symptom but not the owner — nothing tells the operator which workspace is holding the sessions, and the count includes sessions whose processes are gone.

Report the top workspaces by session count in that error, so the message points at the cause rather than at whoever asked next.

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      , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
       blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

      Skip to content
      Tower spawns the process before checking the 100-session cap, so every rejected create leaks one #171
      Open
      Open
      Tower spawns the process before checking the 100-session cap, so every rejected create leaks one#171
      Labels
      area/towerTower, afx, terminals, messaging
      Description
      @pseudoseed
      pseudoseed
      opened on Aug 29, 2026
      Tower is wedged at its 100-session cap and cannot create terminals. Worse, each rejected attempt leaks the process it just spawned, so the condition amplifies itself the longer it lasts.
      The leak
      From ~/.agent-farm/tower.log:
      [06:53:00.936] [INFO] Creating session 7c7ce4ed…: command=/bin/bash, socket=…
[06:53:01.088] [INFO] Session 7c7ce4ed… created: pid=22158
[06:53:01.089] [WARN] Shellper creation failed for terminal, falling back: Maximum 100 sessions reached
[06:53:01.089] [ERROR] Failed to create terminal: Maximum 100 sessions reached

      The order is the bug. Tower spawns the process first, then checks the cap, then reports failure — and does not kill what it just started. pid=22158 is still running, parented to Tower (ppid 44799), long after the request that created it was reported as failed.
      So every terminal request made while at the cap adds one more orphaned /bin/bash under a shellper. The fuller Tower gets, the faster it fills.
      Not every leak is silent: a second attempt in the same second logged Session bbc6c8c4… exited (code=127). So some spawns do exit and some do not, which is why the leak looks intermittent rather than one-per-attempt.
      Scale observed
      • 148Maximum 100 sessions reached entries since 2026-08-28T22:52:38Z, roughly 8 hours.
      • 157 live shellper processes holding about 2.4 GB.
      • 127 of them belong to a workspace with no active work in it, whose last real log entry is from Aug 16.
      • Process start times cluster in bursts matching the cap-hit bursts: 64 in one hour, 25 in the next.
      • 29 of the shellpers have been reparented to init (ppid 1), so Tower is no longer tracking them at all.
      Two separate defects
      1. Spawn-then-check. Check the cap before spawning. If the check must stay where it is, kill the just-created session on the failure path before returning the error. A failed create must leave nothing behind.
      2. Nothing reaps dead sessions. Tower counts 100 sessions against a cap of 100 while the workspaces that own most of them have no live work. Whatever removes a session from the count is not running, or is not reached when a shellper dies unexpectedly. Reconcile the session table against live processes periodically, and on every cap rejection, so the cap reflects reality rather than accumulated bookkeeping.
      Operator impact
      This presents as "I cannot open a terminal" with no indication of why, in a workspace that is not the one at fault. The error surfaced to the caller is Failed to create terminal: Maximum 100 sessions reached, which names the symptom but not the owner — nothing tells the operator which workspace is holding the sessions, and the count includes sessions whose processes are gone.
      Report the top workspaces by session count in that error, so the message points at the cause rather than at whoever asked next.
      Activity
      Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

          Skip to content
          Tower spawns the process before checking the 100-session cap, so every rejected create leaks one #171
          Open
          Open
          Tower spawns the process before checking the 100-session cap, so every rejected create leaks one#171
          Labels
          area/towerTower, afx, terminals, messaging
          Description
          @pseudoseed
          pseudoseed
          opened on Aug 29, 2026
          Tower is wedged at its 100-session cap and cannot create terminals. Worse, each rejected attempt leaks the process it just spawned, so the condition amplifies itself the longer it lasts.
          The leak
          From ~/.agent-farm/tower.log:
          [06:53:00.936] [INFO] Creating session 7c7ce4ed…: command=/bin/bash, socket=…
[06:53:01.088] [INFO] Session 7c7ce4ed… created: pid=22158
[06:53:01.089] [WARN] Shellper creation failed for terminal, falling back: Maximum 100 sessions reached
[06:53:01.089] [ERROR] Failed to create terminal: Maximum 100 sessions reached

          The order is the bug. Tower spawns the process first, then checks the cap, then reports failure — and does not kill what it just started. pid=22158 is still running, parented to Tower (ppid 44799), long after the request that created it was reported as failed.
          So every terminal request made while at the cap adds one more orphaned /bin/bash under a shellper. The fuller Tower gets, the faster it fills.
          Not every leak is silent: a second attempt in the same second logged Session bbc6c8c4… exited (code=127). So some spawns do exit and some do not, which is why the leak looks intermittent rather than one-per-attempt.
          Scale observed
          • 148Maximum 100 sessions reached entries since 2026-08-28T22:52:38Z, roughly 8 hours.
          • 157 live shellper processes holding about 2.4 GB.
          • 127 of them belong to a workspace with no active work in it, whose last real log entry is from Aug 16.
          • Process start times cluster in bursts matching the cap-hit bursts: 64 in one hour, 25 in the next.
          • 29 of the shellpers have been reparented to init (ppid 1), so Tower is no longer tracking them at all.
          Two separate defects
          1. Spawn-then-check. Check the cap before spawning. If the check must stay where it is, kill the just-created session on the failure path before returning the error. A failed create must leave nothing behind.
          2. Nothing reaps dead sessions. Tower counts 100 sessions against a cap of 100 while the workspaces that own most of them have no live work. Whatever removes a session from the count is not running, or is not reached when a shellper dies unexpectedly. Reconcile the session table against live processes periodically, and on every cap rejection, so the cap reflects reality rather than accumulated bookkeeping.
          Operator impact
          This presents as "I cannot open a terminal" with no indication of why, in a workspace that is not the one at fault. The error surfaced to the caller is Failed to create terminal: Maximum 100 sessions reached, which names the symptom but not the owner — nothing tells the operator which workspace is holding the sessions, and the count includes sessions whose processes are gone.
          Report the top workspaces by session count in that error, so the message points at the cause rather than at whoever asked next.
          Activity
          Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
          Metadata
          Metadata
          Assignees
          No one assigned
            Labels
            area/towerTower, afx, terminals, messaging
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              No milestone
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              No branches or pull requests
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

              Skip to content
              Tower spawns the process before checking the 100-session cap, so every rejected create leaks one #171
              Open
              Open
              Tower spawns the process before checking the 100-session cap, so every rejected create leaks one#171
              Labels
              area/towerTower, afx, terminals, messaging
              Description
              @pseudoseed
              pseudoseed
              opened on Aug 29, 2026
              Tower is wedged at its 100-session cap and cannot create terminals. Worse, each rejected attempt leaks the process it just spawned, so the condition amplifies itself the longer it lasts.
              The leak
              From ~/.agent-farm/tower.log:
              [06:53:00.936] [INFO] Creating session 7c7ce4ed…: command=/bin/bash, socket=…
[06:53:01.088] [INFO] Session 7c7ce4ed… created: pid=22158
[06:53:01.089] [WARN] Shellper creation failed for terminal, falling back: Maximum 100 sessions reached
[06:53:01.089] [ERROR] Failed to create terminal: Maximum 100 sessions reached

              The order is the bug. Tower spawns the process first, then checks the cap, then reports failure — and does not kill what it just started. pid=22158 is still running, parented to Tower (ppid 44799), long after the request that created it was reported as failed.
              So every terminal request made while at the cap adds one more orphaned /bin/bash under a shellper. The fuller Tower gets, the faster it fills.
              Not every leak is silent: a second attempt in the same second logged Session bbc6c8c4… exited (code=127). So some spawns do exit and some do not, which is why the leak looks intermittent rather than one-per-attempt.
              Scale observed
              • 148Maximum 100 sessions reached entries since 2026-08-28T22:52:38Z, roughly 8 hours.
              • 157 live shellper processes holding about 2.4 GB.
              • 127 of them belong to a workspace with no active work in it, whose last real log entry is from Aug 16.
              • Process start times cluster in bursts matching the cap-hit bursts: 64 in one hour, 25 in the next.
              • 29 of the shellpers have been reparented to init (ppid 1), so Tower is no longer tracking them at all.
              Two separate defects
              1. Spawn-then-check. Check the cap before spawning. If the check must stay where it is, kill the just-created session on the failure path before returning the error. A failed create must leave nothing behind.
              2. Nothing reaps dead sessions. Tower counts 100 sessions against a cap of 100 while the workspaces that own most of them have no live work. Whatever removes a session from the count is not running, or is not reached when a shellper dies unexpectedly. Reconcile the session table against live processes periodically, and on every cap rejection, so the cap reflects reality rather than accumulated bookkeeping.
              Operator impact
              This presents as "I cannot open a terminal" with no indication of why, in a workspace that is not the one at fault. The error surfaced to the caller is Failed to create terminal: Maximum 100 sessions reached, which names the symptom but not the owner — nothing tells the operator which workspace is holding the sessions, and the count includes sessions whose processes are gone.
              Report the top workspaces by session count in that error, so the message points at the cause rather than at whoever asked next.
              Activity
              Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
              Metadata
              Metadata
              Assignees
              No one assigned
                Labels
                area/towerTower, afx, terminals, messaging
                Projects
                No projects
                  Milestone
                  No milestone
                  Relationships
                  None yet
                  Development
                  No branches or pull requests
                  Issue actions
                  
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

                  Skip to content
                  Tower spawns the process before checking the 100-session cap, so every rejected create leaks one #171
                  Open
                  Open
                  Tower spawns the process before checking the 100-session cap, so every rejected create leaks one#171
                  Labels
                  area/towerTower, afx, terminals, messaging
                  Description
                  @pseudoseed
                  pseudoseed
                  opened on Aug 29, 2026
                  Tower is wedged at its 100-session cap and cannot create terminals. Worse, each rejected attempt leaks the process it just spawned, so the condition amplifies itself the longer it lasts.
                  The leak
                  From ~/.agent-farm/tower.log:
                  [06:53:00.936] [INFO] Creating session 7c7ce4ed…: command=/bin/bash, socket=…
[06:53:01.088] [INFO] Session 7c7ce4ed… created: pid=22158
[06:53:01.089] [WARN] Shellper creation failed for terminal, falling back: Maximum 100 sessions reached
[06:53:01.089] [ERROR] Failed to create terminal: Maximum 100 sessions reached

                  The order is the bug. Tower spawns the process first, then checks the cap, then reports failure — and does not kill what it just started. pid=22158 is still running, parented to Tower (ppid 44799), long after the request that created it was reported as failed.
                  So every terminal request made while at the cap adds one more orphaned /bin/bash under a shellper. The fuller Tower gets, the faster it fills.
                  Not every leak is silent: a second attempt in the same second logged Session bbc6c8c4… exited (code=127). So some spawns do exit and some do not, which is why the leak looks intermittent rather than one-per-attempt.
                  Scale observed
                  • 148Maximum 100 sessions reached entries since 2026-08-28T22:52:38Z, roughly 8 hours.
                  • 157 live shellper processes holding about 2.4 GB.
                  • 127 of them belong to a workspace with no active work in it, whose last real log entry is from Aug 16.
                  • Process start times cluster in bursts matching the cap-hit bursts: 64 in one hour, 25 in the next.
                  • 29 of the shellpers have been reparented to init (ppid 1), so Tower is no longer tracking them at all.
                  Two separate defects
                  1. Spawn-then-check. Check the cap before spawning. If the check must stay where it is, kill the just-created session on the failure path before returning the error. A failed create must leave nothing behind.
                  2. Nothing reaps dead sessions. Tower counts 100 sessions against a cap of 100 while the workspaces that own most of them have no live work. Whatever removes a session from the count is not running, or is not reached when a shellper dies unexpectedly. Reconcile the session table against live processes periodically, and on every cap rejection, so the cap reflects reality rather than accumulated bookkeeping.
                  Operator impact
                  This presents as "I cannot open a terminal" with no indication of why, in a workspace that is not the one at fault. The error surfaced to the caller is Failed to create terminal: Maximum 100 sessions reached, which names the symptom but not the owner — nothing tells the operator which workspace is holding the sessions, and the count includes sessions whose processes are gone.
                  Report the top workspaces by session count in that error, so the message points at the cause rather than at whoever asked next.
                  Activity
                  Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
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                  Metadata
                  Assignees
                  No one assigned
                    Labels
                    area/towerTower, afx, terminals, messaging
                    Projects
                    No projects
                      Milestone
                      No milestone
                      Relationships
                      None yet
                      Development
                      No branches or pull requests
                      Issue actions
                      
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

                      Skip to content
                      Tower spawns the process before checking the 100-session cap, so every rejected create leaks one #171
                      Open
                      Open
                      Tower spawns the process before checking the 100-session cap, so every rejected create leaks one#171
                      Labels
                      area/towerTower, afx, terminals, messaging
                      Description
                      @pseudoseed
                      pseudoseed
                      opened on Aug 29, 2026
                      Tower is wedged at its 100-session cap and cannot create terminals. Worse, each rejected attempt leaks the process it just spawned, so the condition amplifies itself the longer it lasts.
                      The leak
                      From ~/.agent-farm/tower.log:
                      [06:53:00.936] [INFO] Creating session 7c7ce4ed…: command=/bin/bash, socket=…
[06:53:01.088] [INFO] Session 7c7ce4ed… created: pid=22158
[06:53:01.089] [WARN] Shellper creation failed for terminal, falling back: Maximum 100 sessions reached
[06:53:01.089] [ERROR] Failed to create terminal: Maximum 100 sessions reached

                      The order is the bug. Tower spawns the process first, then checks the cap, then reports failure — and does not kill what it just started. pid=22158 is still running, parented to Tower (ppid 44799), long after the request that created it was reported as failed.
                      So every terminal request made while at the cap adds one more orphaned /bin/bash under a shellper. The fuller Tower gets, the faster it fills.
                      Not every leak is silent: a second attempt in the same second logged Session bbc6c8c4… exited (code=127). So some spawns do exit and some do not, which is why the leak looks intermittent rather than one-per-attempt.
                      Scale observed
                      • 148Maximum 100 sessions reached entries since 2026-08-28T22:52:38Z, roughly 8 hours.
                      • 157 live shellper processes holding about 2.4 GB.
                      • 127 of them belong to a workspace with no active work in it, whose last real log entry is from Aug 16.
                      • Process start times cluster in bursts matching the cap-hit bursts: 64 in one hour, 25 in the next.
                      • 29 of the shellpers have been reparented to init (ppid 1), so Tower is no longer tracking them at all.
                      Two separate defects
                      1. Spawn-then-check. Check the cap before spawning. If the check must stay where it is, kill the just-created session on the failure path before returning the error. A failed create must leave nothing behind.
                      2. Nothing reaps dead sessions. Tower counts 100 sessions against a cap of 100 while the workspaces that own most of them have no live work. Whatever removes a session from the count is not running, or is not reached when a shellper dies unexpectedly. Reconcile the session table against live processes periodically, and on every cap rejection, so the cap reflects reality rather than accumulated bookkeeping.
                      Operator impact
                      This presents as "I cannot open a terminal" with no indication of why, in a workspace that is not the one at fault. The error surfaced to the caller is Failed to create terminal: Maximum 100 sessions reached, which names the symptom but not the owner — nothing tells the operator which workspace is holding the sessions, and the count includes sessions whose processes are gone.
                      Report the top workspaces by session count in that error, so the message points at the cause rather than at whoever asked next.
                      Activity
                      Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
                      Metadata
                      Metadata
                      Assignees
                      No one assigned
                        Labels
                        area/towerTower, afx, terminals, messaging
                        Projects
                        No projects
                          Milestone
                          No milestone
                          Relationships
                          None yet
                          Development
                          No branches or pull requests
                          Issue actions
                          
, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

                          Skip to content
                          Tower spawns the process before checking the 100-session cap, so every rejected create leaks one #171
                          Open
                          Open
                          Tower spawns the process before checking the 100-session cap, so every rejected create leaks one#171
                          Labels
                          area/towerTower, afx, terminals, messaging
                          Description
                          @pseudoseed
                          pseudoseed
                          opened on Aug 29, 2026
                          Tower is wedged at its 100-session cap and cannot create terminals. Worse, each rejected attempt leaks the process it just spawned, so the condition amplifies itself the longer it lasts.
                          The leak
                          From ~/.agent-farm/tower.log:
                          [06:53:00.936] [INFO] Creating session 7c7ce4ed…: command=/bin/bash, socket=…
[06:53:01.088] [INFO] Session 7c7ce4ed… created: pid=22158
[06:53:01.089] [WARN] Shellper creation failed for terminal, falling back: Maximum 100 sessions reached
[06:53:01.089] [ERROR] Failed to create terminal: Maximum 100 sessions reached

                          The order is the bug. Tower spawns the process first, then checks the cap, then reports failure — and does not kill what it just started. pid=22158 is still running, parented to Tower (ppid 44799), long after the request that created it was reported as failed.
                          So every terminal request made while at the cap adds one more orphaned /bin/bash under a shellper. The fuller Tower gets, the faster it fills.
                          Not every leak is silent: a second attempt in the same second logged Session bbc6c8c4… exited (code=127). So some spawns do exit and some do not, which is why the leak looks intermittent rather than one-per-attempt.
                          Scale observed
                          • 148Maximum 100 sessions reached entries since 2026-08-28T22:52:38Z, roughly 8 hours.
                          • 157 live shellper processes holding about 2.4 GB.
                          • 127 of them belong to a workspace with no active work in it, whose last real log entry is from Aug 16.
                          • Process start times cluster in bursts matching the cap-hit bursts: 64 in one hour, 25 in the next.
                          • 29 of the shellpers have been reparented to init (ppid 1), so Tower is no longer tracking them at all.
                          Two separate defects
                          1. Spawn-then-check. Check the cap before spawning. If the check must stay where it is, kill the just-created session on the failure path before returning the error. A failed create must leave nothing behind.
                          2. Nothing reaps dead sessions. Tower counts 100 sessions against a cap of 100 while the workspaces that own most of them have no live work. Whatever removes a session from the count is not running, or is not reached when a shellper dies unexpectedly. Reconcile the session table against live processes periodically, and on every cap rejection, so the cap reflects reality rather than accumulated bookkeeping.
                          Operator impact
                          This presents as "I cannot open a terminal" with no indication of why, in a workspace that is not the one at fault. The error surfaced to the caller is Failed to create terminal: Maximum 100 sessions reached, which names the symptom but not the owner — nothing tells the operator which workspace is holding the sessions, and the count includes sessions whose processes are gone.
                          Report the top workspaces by session count in that error, so the message points at the cause rather than at whoever asked next.
                          Activity
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

                              Skip to content
                              Tower spawns the process before checking the 100-session cap, so every rejected create leaks one #171
                              Open
                              Open
                              Tower spawns the process before checking the 100-session cap, so every rejected create leaks one#171
                              Labels
                              area/towerTower, afx, terminals, messaging
                              Description
                              @pseudoseed
                              pseudoseed
                              opened on Aug 29, 2026
                              Tower is wedged at its 100-session cap and cannot create terminals. Worse, each rejected attempt leaks the process it just spawned, so the condition amplifies itself the longer it lasts.
                              The leak
                              From ~/.agent-farm/tower.log:
                              [06:53:00.936] [INFO] Creating session 7c7ce4ed…: command=/bin/bash, socket=…
[06:53:01.088] [INFO] Session 7c7ce4ed… created: pid=22158
[06:53:01.089] [WARN] Shellper creation failed for terminal, falling back: Maximum 100 sessions reached
[06:53:01.089] [ERROR] Failed to create terminal: Maximum 100 sessions reached

                              The order is the bug. Tower spawns the process first, then checks the cap, then reports failure — and does not kill what it just started. pid=22158 is still running, parented to Tower (ppid 44799), long after the request that created it was reported as failed.
                              So every terminal request made while at the cap adds one more orphaned /bin/bash under a shellper. The fuller Tower gets, the faster it fills.
                              Not every leak is silent: a second attempt in the same second logged Session bbc6c8c4… exited (code=127). So some spawns do exit and some do not, which is why the leak looks intermittent rather than one-per-attempt.
                              Scale observed
                              • 148Maximum 100 sessions reached entries since 2026-08-28T22:52:38Z, roughly 8 hours.
                              • 157 live shellper processes holding about 2.4 GB.
                              • 127 of them belong to a workspace with no active work in it, whose last real log entry is from Aug 16.
                              • Process start times cluster in bursts matching the cap-hit bursts: 64 in one hour, 25 in the next.
                              • 29 of the shellpers have been reparented to init (ppid 1), so Tower is no longer tracking them at all.
                              Two separate defects
                              1. Spawn-then-check. Check the cap before spawning. If the check must stay where it is, kill the just-created session on the failure path before returning the error. A failed create must leave nothing behind.
                              2. Nothing reaps dead sessions. Tower counts 100 sessions against a cap of 100 while the workspaces that own most of them have no live work. Whatever removes a session from the count is not running, or is not reached when a shellper dies unexpectedly. Reconcile the session table against live processes periodically, and on every cap rejection, so the cap reflects reality rather than accumulated bookkeeping.
                              Operator impact
                              This presents as "I cannot open a terminal" with no indication of why, in a workspace that is not the one at fault. The error surfaced to the caller is Failed to create terminal: Maximum 100 sessions reached, which names the symptom but not the owner — nothing tells the operator which workspace is holding the sessions, and the count includes sessions whose processes are gone.
                              Report the top workspaces by session count in that error, so the message points at the cause rather than at whoever asked next.
                              Activity
                              Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
                              Metadata
                              Metadata
                              Assignees
                              No one assigned
                                Labels
                                area/towerTower, afx, terminals, messaging
                                Projects
                                No projects
                                  Milestone
                                  No milestone
                                  Relationships
                                  None yet
                                  Development
                                  No branches or pull requests
                                  Issue actions