date-threshold-arithmetic SKILL.md skillA
date-threshold-arithmetic from fabioc-aloha/alex_skill_mall is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add fabioc-aloha/alex_skill_mall/date-threshold-arithmetic@git:20260728.80a7ab6Pins git:20260728.80a7ab6 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- fabioc-aloha/alex_skill_mall
- Path
plugins/code-quality/date-threshold-arithmetic/skills/date-threshold-arithmetic/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260728.80a7ab6, committed Jul 28, 2026
- Size
- 1,983 bytes
- Repository stars
- 5
- License
- MIT
Date comparisons at thresholds fail due to fractional days:.
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
# Date Threshold Arithmetic
## The Problem
Date comparisons at thresholds fail due to fractional days:
```javascript
const daysBetween = (Date.now() - someDate.getTime()) / (1000 * 60 * 60 * 24);
// someDate is "exactly 7 days ago"
// daysBetween = 7.000012 (due to milliseconds)
// if (daysBetween > 7) { ... } // TRUE — unexpected!
```
## The Solution
Always `Math.floor()` before threshold comparison.
```javascript
function daysSince(date) {
const ms = Date.now() - new Date(date).getTime();
return Math.floor(ms / (1000 * 60 * 60 * 24));
}
// Now "exactly 7 days" = 7, not 7.000012
if (daysSince(lastCheck) > 7) {
// Truly more than 7 full days
}
```
## Common Traps
| Code | Bug |
|------|-----|
| `days > 7` | Triggers on 7.0001 |
| `days >= 7` | Doesn't trigger on 6.9999 |
| `days === 7` | Never true for fractional values |
## Safe Patterns
```javascript
// Days since (full days only)
const fullDays = Math.floor((now - then) / MS_PER_DAY);
// Is it past the threshold?
if (fullDays > threshold) { ... }
// Is it on or past the threshold?
if (fullDays >= threshold) { ... }
// Is it exactly N days?
if (fullDays === threshold) { ... }
```
## For Cron-Style Checks
…Read the whole file at its exact version.
How to install
mdr add fabioc-aloha/alex_skill_mall/date-threshold-arithmetic@sha256:d5e7c685dca8fd16The line at the top of this page pins the label git:20260728.80a7ab6, 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_tp6chzpw5huh2gy3)
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Versions
The registry has recorded 1 version of this file, committed on Jul 28, 2026.
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 (1983 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
fabioc-aloha/alex_skill_mall · 5 stars · license MIT · pushed 2026-11-06 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_tp6chzpw5huh2gy3 GET https://markdownregistry.com/api/v1/resolve?ref=fabioc-aloha/alex_skill_mall/date-threshold-arithmetic GET https://markdownregistry.com/api/v1/blob/d5e7c685dca8fd162f36ceadd16d0be7c4cd137c7fe12c705c55eeedb30fdd9a
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.