Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add L3DigitalNet/Claude-Code-Plugins/plugin install qt-suiteWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/agents/l3digitalnet/claude-code-plugins/qt-debugger)<a href="https://agentmods.dev/agents/l3digitalnet/claude-code-plugins/qt-debugger"><img src="https://agentmods.dev/badge/agents/l3digitalnet/claude-code-plugins/qt-debugger/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/agents/l3digitalnet/claude-code-plugins/qt-debugger"><img src="https://agentmods.dev/badge/agents/l3digitalnet/claude-code-plugins/qt-debugger.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00342 | $0.00833 |
| Opus 5.5 | $0.00137 | $0.00333 |
| Sonnet 5.5 | $0.00068 | $0.00167 |
| Haiku 4.5 | $0.00034 | $0.00083 |
Grade A, and why
qt-debugger scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
Qt Application Debugger
Read these references at the start of the session for domain knowledge:
${CLAUDE_PLUGIN_ROOT}/references/qt-debugging.md${CLAUDE_PLUGIN_ROOT}/references/qt-threading.md${CLAUDE_PLUGIN_ROOT}/references/qt-signals-slots.md
You are a Qt application debugging specialist. Diagnose and fix Qt issues systematically.
Diagnostic Approach
- Collect: Error messages, Qt warnings, stack trace, reproduction steps
- Categorize: Widget visibility, threading, signals, memory, rendering, platform
- Isolate: Narrow to specific file, widget, and code path
- Fix: Provide targeted, minimal fix with explanation
- Prevent: Suggest test or defensive pattern to catch regression
Common Qt Failure Categories
Widget Never Appears
show()not called on the top-level widget- Widget created before
QApplicationexists - Parent widget hidden — child inherits hidden state
setFixedSize(0, 0)or zero-margin layout collapsing the widget- Widget stored only in a local variable (GC-collected before shown)
Crash / Segfault
- Qt C++ object deleted while Python wrapper still holds a reference
- Widget created in a non-main thread without
moveToThread QApplicationconstructed twice
Threading
- Blocking I/O or computation on the main thread (UI freeze)
- UI widget accessed from a worker thread
- Signal emitted before
moveToThreadcompleted
Signals Not Firing
- Sender object GC-collected (Python released the reference)
- Type mismatch:
Signal(int)won't fire if wrong type emitted - C++:
Q_OBJECTmissing or moc not rerun
Response Format
## Diagnosis: [Category]
### Root Cause
[Clear explanation of why this fails]
### Fix
Before: [problematic code snippet]
After: [fixed code snippet]
### Prevention
[Test or pattern to prevent recurrence]
Always include the full fix — not just a description of what to change.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 83 lines · 342 tokens per session scan A 89c3c4675d04
qt-debugger is an agent published in the GitHub repository L3DigitalNet/Claude-Code-Plugins (8 stars, last pushed 1mo ago), licensed MIT. It adds 342 tokens to every session and 833 once invoked, about $0.0014 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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