derivation-windowing SKILL.md skillA
derivation-windowing from estuary/agent-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add estuary/agent-skills/derivation-windowing@git:20260707.6b608bfPins git:20260707.6b608bf in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- estuary/agent-skills
- Path
skills/derivation-windowing/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260707.6b608bf, committed Jul 7, 2026
- Size
- 14,449 bytes
- Repository stars
- 7
- License
- Apache-2.0
Create an Estuary derivation that maintains a sliding time window of events (e.g. "transfers in the last 24h", "failed logins in the last 5 minutes") using internal SQLite state and readDelay for time-based expiration. Derivations add complexity and cost — confirm the user wants a derivation before reaching for this. Use when user says "windowing derivation", "derivation for last-24h events", "rolling-window derivation", "sliding-window transformation", "fraud-detection derivation…
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
# derivation-windowing Estuary derivation that maintains a **sliding time window** of events per key — events enter the window on arrival and leave it after a fixed delay. Typically used for fraud detection, rate limiting, or "recent activity" signals. **Prereq:** read `derivation-basics` first. This skill is the most complex of the set — it combines internal SQLite state (like `derivation-stateful-logic`) with a second transform using `readDelay` to age events out of the window. **Docs:** - https://docs.estuary.dev/getting-started/tutorials/derivations_acmebank/#grouped-windows-of-transfers — the canonical walkthrough for this exact pattern - https://docs.estuary.dev/concepts/derivations/#internal-state — internal state mechanics ## When to use this over alternatives - **Sliding / rolling windows**: "last 24h of high-value transfers", "last 5min of failed logins" - **Time-bounded rate limits**: "more than 10 requests per user in the last minute" - **Fraud / anomaly signals**: "user did X more than N times within a window" - **Real-time dashboards** showing "activity in the last hour" Reach for other skills when: …
Read the whole file at its exact version.
How to install
mdr add estuary/agent-skills/derivation-windowing@sha256:14313a59f64e31b5The line at the top of this page pins the label git:20260707.6b608bf, 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_b3r4mplo2pwfzyvl)
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Versions
The registry has recorded 1 version of this file, committed on Jul 7, 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 (14449 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
estuary/agent-skills · 7 stars · license Apache-2.0 · pushed 2026-11-04 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_b3r4mplo2pwfzyvl GET https://markdownregistry.com/api/v1/resolve?ref=estuary/agent-skills/derivation-windowing GET https://markdownregistry.com/api/v1/blob/14313a59f64e31b50cb8f70d74b86e2ea586df0035e408938ace0c64e476aa93
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.