backfill

backfill is a command for Claude Code from vaquarkhan/data-engineering-agent-skills. It costs 0 tokens per session (176 once invoked), scanned A, original, MIT.

A command for planning safe data backfills, replays, and cutovers. A backfill is filling or correcting data for an existing time range; a cutover is switching from an old system or process to a new one.

In plain words
What is it for?
Use it before rerunning jobs, replaying events, migrating data, or switching systems. It helps prepare the plan and run available safety checks before execution.
Why use it?
Repeating data work can duplicate records or leave systems inconsistent. This requires a defined affected range, rollback plan, retry behavior, and checks that confirm the result.

Command for Claude Code

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.

agentmods
npx agentmods add commands/vaquarkhan/data-engineering-agent-skills/backfill
Clone the repo
git clone --depth 1 https://github.com/vaquarkhan/data-engineering-agent-skills

Made for: Claude Code.

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 backfill

README.md
[![agentmods](https://agentmods.dev/badge/commands/vaquarkhan/data-engineering-agent-skills/backfill.svg)](https://agentmods.dev/commands/vaquarkhan/data-engineering-agent-skills/backfill)
Your own site
<a href="https://agentmods.dev/commands/vaquarkhan/data-engineering-agent-skills/backfill"><img src="https://agentmods.dev/badge/commands/vaquarkhan/data-engineering-agent-skills/backfill.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 176 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00000 $0.00176
Opus 5 $0.00000 $0.00088
Sonnet 5 $0.00000 $0.00035
Haiku 4.5 $0.00000 $0.00018

Measured 5d ago against content hash 6a4e1654a2f7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

backfill 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.

.claude/commands/backfill.md · 14 lines

What it actually says

/backfill

Use replay-safe workflows before rerunning, replaying, or cutting over data.

Checklist:

  1. load safe-backfill-and-replay-orchestration first — draft templates/backfill-plan.yaml before any execution
  2. run hooks/backfill-guard.sh or hooks/backfill-guard.ps1 when available
  3. load orchestration-and-backfills for schedule, retry, and dependency semantics
  4. load data-migration-and-platform-cutover for cutovers or dual-run changes
  5. load data-reconciliation-and-financial-controls when correctness must be proven after replay
  6. load mcp-data-observability-integration when live lag or run state should inform the replay window
  7. define the affected window, rollback path, and reconciliation gates before execution
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. 5d ago First seen · 14 lines · 0 tokens per session scan A 6a4e1654a2f7

Subscribe to this mod's changes

backfill is a command published in the GitHub repository vaquarkhan/data-engineering-agent-skills (40 stars, last pushed 2mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 176 tokens. 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.