gotchas SKILL.md skillA
gotchas from qutone/lightstim is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add qutone/lightstim/gotchas@git:20260526.26119ebPins git:20260526.26119eb in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- qutone/lightstim
- Path
skills/gotchas/SKILL.md- Versions recorded
- 4
- Latest version
- git:20260526.26119eb, committed May 26, 2026
- First version recorded
- May 25, 2026
- Size
- 22,050 bytes
- Repository stars
- 50
- License
- a license file GitHub does not identify
LightStim known pitfalls, bugs, and non-obvious API contracts. Read this whenever a build produces unexpected results, the tracker raises a RuntimeError, noiseless-check detections appear, LER is suspiciously high, or the user reports "it was working and now it isn't." Each entry states the symptom, the root cause, and the fix pattern.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# LightStim Gotchas & Common Pitfalls
A living catalogue of non-obvious bugs and API contracts discovered during
development. When something goes wrong, scan the symptom descriptions first —
most bugs fall into one of these categories.
---
## 1. Coupler Pitfalls
### 1-A `system.data_indices` includes coupler qubits after `register_coupler()`
**Symptom**: Tracker raises `RuntimeError: Logical Count Mismatch! Expected N, Found M`
where M ≫ N, often during the *first* `apply_syndrome_extraction` after batch
initialization.
**Root cause**: `register_coupler()` allocates new data qubits (the ancilla corridor
between patches) and adds them to `system.data_indices` and `system.index_to_owner_map`
(owner = the coupler name, e.g. `'coupler_23'`). If you batch-initialize all of
`system.data_indices` you also initialize the coupler's corridor qubits, injecting
M − N phantom "logical" rows into the tracker.
**Fix**: Filter by owner when doing batch init:
```python
coupler_names = set(system.coupler_patches.keys())
patch_data = {q: 'X' for q in system.data_indices
if system.index_to_owner_map.get(q) not in coupler_names}
…Read the whole file at its exact version.
How to install
mdr add qutone/lightstim/gotchas@sha256:925d5517d9ce6e14The line at the top of this page pins the label git:20260526.26119eb, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_6m47hlmsbfkiwswx)
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Versions
The registry has recorded 4 versions of this file, between May 25, 2026 and May 26, 2026, more than one a day.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260526.26119eb latest | 2026-05-26 | 26119eb | 22,050 B | A | view · diff |
| git:20260526.5b92aea | 2026-05-26 | 5b92aea | 20,965 B | A | view · diff |
| git:20260525.3780051 | 2026-05-25 | 3780051 | 14,221 B | A | view · diff |
| git:20260525.485b99d | 2026-05-25 | 485b99d | 13,303 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (22050 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
qutone/lightstim · 50 stars · license a license file GitHub does not identify · pushed 2026-10-29 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_6m47hlmsbfkiwswx GET https://markdownregistry.com/api/v1/resolve?ref=qutone/lightstim/gotchas GET https://markdownregistry.com/api/v1/blob/925d5517d9ce6e14b93b34ad610b2fe3d3b46ff27d7c5944204e7508ae041de5
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.
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