cdc-and-incremental-loading

cdc-and-incremental-loading is a skill for Claude Code, Codex from vaquarkhan/data-engineering-agent-skills. It costs 48 tokens per session (507 once invoked), scanned A, original, MIT.

A guide for loading only data that changed instead of rebuilding an entire data set. It covers change data capture, which records inserts, updates, and deletes as they happen.

In plain words
What is it for?
Use it to design incremental data pipelines with watermarks, upserts, deduplication, delete handling, retries, and replay.
Why use it?
It helps prevent missed changes, duplicate records, and unsafe reruns when data arrives late or loads fail partway through.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to design incremental data pipelines with watermarks, upserts, deduplication, delete handling, retries, and replay.

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Install with agentmods
npx agentmods add skills/vaquarkhan/data-engineering-agent-skills/cdc-and-incremental-loading
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add vaquarkhan/data-engineering-agent-skills --skill cdc-and-incremental-loading
Clone the repo
git clone --depth 1 https://github.com/vaquarkhan/data-engineering-agent-skills

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for cdc-and-incremental-loading

README.md
[![agentmods](https://agentmods.dev/badge/skills/vaquarkhan/data-engineering-agent-skills/cdc-and-incremental-loading.svg)](https://agentmods.dev/skills/vaquarkhan/data-engineering-agent-skills/cdc-and-incremental-loading)
Your own site
<a href="https://agentmods.dev/skills/vaquarkhan/data-engineering-agent-skills/cdc-and-incremental-loading"><img src="https://agentmods.dev/badge/skills/vaquarkhan/data-engineering-agent-skills/cdc-and-incremental-loading.svg" alt="Measured on agentmods" height="20"></a>
Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 507 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00048 $0.00507
Opus 5 $0.00024 $0.00253
Sonnet 5 $0.00010 $0.00101
Haiku 4.5 $0.00005 $0.00051

Measured 8d ago against content hash 29f21c14a0de, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

cdc-and-incremental-loading 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 8d 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.

skills/cdc-and-incremental-loading/SKILL.md · 73 lines

How it starts

The opening of the file, as written. The whole thing — 73 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CDC And Incremental Loading

Overview

Use this skill when the system changes data over time and full reloads are not the right answer. It helps agents design safe incremental behavior with clear watermarks, merge rules, deduplication, and replay semantics.

When to Use

  • implementing CDC ingestion
  • designing watermark-based or timestamp-based incremental loads
  • merging inserts, updates, and deletes
  • handling late-arriving data
  • fixing duplicate or missing incremental records

Do not use this when a bounded full refresh is simpler and operationally safer.

Workflow

  1. Define the change contract. Include:

    • business key
    • change key or sequence
    • delete behavior
    • update semantics
    • source ordering guarantees
  2. Choose the incremental strategy. Typical options:

    • append-only
    • merge/upsert
    • snapshot replacement
    • log-based CDC
  3. Make watermark logic explicit. Record:

    • watermark column
    • lag tolerance
    • reprocessing window
    • retry and replay rules
  4. Guard against duplicates and missed changes. Deduplication and late-data handling should be first-class logic.

  5. Prove reruns are safe. Incremental pipelines that cannot be replayed safely are incomplete.

Common Rationalizations

Rationalization Reality
"We can just use updated_at as the watermark." Timestamps alone often miss late changes, clock skew, or delete semantics.
"Duplicates are rare enough." Rare duplicates are still expensive when they affect published metrics.
"We can rebuild everything if something goes wrong." Large backfills are often slow, expensive, or operationally risky.

Red Flags

  • no documented business key
  • delete handling is absent
  • watermark logic depends on assumptions no one wrote down
  • replay requires manual surgery in production tables

Verification

  • The incremental contract covers inserts, updates, and deletes where relevant
  • Watermark, lag, deduplication, and replay rules are explicit
  • Late data behavior is defined
  • Reruns and backfills are operationally safe

Read the full file on GitHub · 73 lines

Changes

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.

  1. 8d ago First seen · 73 lines · 48 tokens per session scan A 29f21c14a0de

Subscribe to this mod's changes

cdc-and-incremental-loading is a skill published in the GitHub repository vaquarkhan/data-engineering-agent-skills (43 stars, last pushed 2mo ago), licensed MIT. It adds 48 tokens to every session and 507 once invoked, about $0.0002 per session on Opus 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.