Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/mendixlabs/mxclinpx agentmods add skills/mendixlabs/mxcli/debug-bsonWrote 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/skills/mendixlabs/mxcli/debug-bson)<a href="https://agentmods.dev/skills/mendixlabs/mxcli/debug-bson"><img src="https://agentmods.dev/badge/skills/mendixlabs/mxcli/debug-bson/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/skills/mendixlabs/mxcli/debug-bson"><img src="https://agentmods.dev/badge/skills/mendixlabs/mxcli/debug-bson.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00056 | $0.05554 |
| Opus 5.5 | $0.00022 | $0.02222 |
| Sonnet 5.5 | $0.00011 | $0.01111 |
| Haiku 4.5 | $0.00006 | $0.00555 |
Grade A, and why
debug-bson scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 627 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Find it fast
sed -n '<from>,<to>p' SKILL.md one section rather than reading the file;
./mxcli syntax <topic> answers how do I write this for a fraction of either.
| lines | section |
|---|---|
| 33-42 | When to Use This Skill |
| 43-51 | Overview |
| 52-111 | Part 1: The Debugging Workflow |
| 112-159 | Part 2: Common BSON Patterns |
| 160-212 | Part 3: Key Structures Reference |
| 213-252 | Part 4: Debugging Tools |
| 253-265 | Part 5: Checklist for BSON Fixes |
| 266-280 | Part 6: Common Issues and Solutions |
| 281-330 | Part 7: Nested WidgetObjects (Critical) |
| 331-412 | Part 8: Property Value Types (Critical) |
| 413-451 | Part 9: Texts$Translation vs Texts$TextItem |
| 452-584 | Part 10: CE0463 TextTemplate Troubleshooting |
| 585-591 | Related Documentation |
| 592-626 | Quick Reference |
BSON Serialization Debugging Skill
This skill provides guidance for debugging BSON serialization issues when implementing or fixing Mendix SDK writers.
When to Use This Skill
Use this skill when:
- Objects created via MDL don't appear correctly in Studio Pro
- Properties are missing, empty, or showing default values
- Widget captions, parameters, or nested structures aren't stored correctly
- You need to compare SDK-generated BSON with Studio Pro-generated BSON
- You encounter "empty" or "(Empty caption)" issues in Studio Pro
- Debugging BSON array version markers or object structures
Overview
When the ModelSDK Go serializes objects to BSON, the output must exactly match what Mendix Studio Pro expects. Even small differences in:
- Field names (e.g.,
captionvsCaptionTemplate) - Object structures (e.g., string vs nested object)
- Array version markers (e.g.,
[2, items...]vs[3, items...])
...can cause Studio Pro to ignore the data entirely.
Part 1: The Debugging Workflow
Step 1: Identify the Problem
Symptoms that indicate BSON serialization issues:
- MDL
describecommand shows correct data, but Studio Pro shows empty/default - Object is created but properties don't persist
- Nested structures (templates, parameters) are missing
- "(Empty caption)" or similar placeholder text in Studio Pro
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.
- 5d ago Changed · +23 lines 0aa0f96ea805
- 28d ago Changed · -6 lines 460262793b4d
- 1mo ago First seen · 610 lines · 56 tokens per session scan A 3cac80ae8941
debug-bson is a skill published in the GitHub repository mendixlabs/mxcli (130 stars, last pushed yesterday), licensed Apache-2.0. It adds 56 tokens to every session and 5,554 once invoked, about $0.0002 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 2026-08-30.
Other skills, from other repositories
codegraph
Analyze indexed codebases via graph database (neug) and vector index (zvec). Covers call graphs, dependencies, dead code, hotspots, module coupling, architecture reports, semantic search, impact analysis, bug root cause from GitHub issues, class diagrams (UML), and PR review (risk scoring, conflict detection…
stuck
Diagnose frozen, stuck, or slow Qwen Code sessions on this machine. Scans for problematic processes, high CPU/memory usage, hung subprocesses, and debug logs. Use /stuck or /stuck to focus on a specific process.
structured-debugging
Hypothesis-driven debugging methodology for hard bugs. Use this skill whenever you're investigating non-trivial bugs, unexpected behavior, flaky tests, or tracing issues through complex systems. Activate proactively when debugging requires more than a quick glance — especially when the first attempt at a fix didn't…
memory-leak-debug
Diagnose memory leaks in the Qwen Code CLI using heap snapshots and the chrome-devtools CLI. Use when investigating high memory usage, unbounded growth, or suspected object retention issues.
bugfix
Fix a bug from a GitHub issue, following the reproduce-first workflow. Use when the user asks to fix a bug, investigate a GitHub issue, or debug a user-reported problem. Takes a GitHub issue URL or number as input.
test-failure-explorer
Import and query an existing Vitest 3.2 JSON report to explore test failures, file-level errors and original diagnostic evidence.