claude-skills is a collection of specialized skills that extends Claude Code for full-stack development. Developers use it for programming languages, frameworks, infrastructure, APIs, testing, DevOps, security, data and machine learning, platform tasks, and project workflows.
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.
npx skills add Jeffallan/claude-skills --skill spark-engineergit clone --depth 1 https://github.com/Jeffallan/claude-skillsWrote 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.
[](https://agentmods.dev/skills/jeffallan/claude-skills/spark-engineer)<a href="https://agentmods.dev/skills/jeffallan/claude-skills/spark-engineer"><img src="https://agentmods.dev/badge/skills/jeffallan/claude-skills/spark-engineer/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/jeffallan/claude-skills/spark-engineer"><img src="https://agentmods.dev/badge/skills/jeffallan/claude-skills/spark-engineer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00075 | $0.01476 |
| Opus 5 | $0.00037 | $0.00738 |
| Sonnet 5 | $0.00015 | $0.00295 |
| Haiku 4.5 | $0.00007 | $0.00148 |
Grade A, and why
spark-engineer 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 10d 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.
Copies of this mod
2 near-identical copies found in the catalogue:
- spark-engineer — 98% identical, 2 lines differ
- spark-engineer — 92% identical, 26 lines differ
How it starts
The opening of the file, as written. The whole thing — 151 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Spark Engineer
Senior Apache Spark engineer specializing in high-performance distributed data processing, optimizing large-scale ETL pipelines, and building production-grade Spark applications.
Core Workflow
- Analyze requirements - Understand data volume, transformations, latency requirements, cluster resources
- Design pipeline - Choose DataFrame vs RDD, plan partitioning strategy, identify broadcast opportunities
- Implement - Write Spark code with optimized transformations, appropriate caching, proper error handling
- Optimize - Analyze Spark UI, tune shuffle partitions, eliminate skew, optimize joins and aggregations
- Validate - Check Spark UI for shuffle spill before proceeding; verify partition count with
df.rdd.getNumPartitions(); if spill or skew detected, return to step 4; test with production-scale data, monitor resource usage, verify performance targets
Reference Guide
Load detailed guidance based on context:
| Topic | Reference | Load When |
|---|---|---|
| Spark SQL & DataFrames | references/spark-sql-dataframes.md |
DataFrame API, Spark SQL, schemas, joins, aggregations |
| RDD Operations | references/rdd-operations.md |
Transformations, actions, pair RDDs, custom partitioners |
| Partitioning & Caching | references/partitioning-caching.md |
Data partitioning, persistence levels, broadcast variables |
| Performance Tuning | references/performance-tuning.md |
Configuration, memory tuning, shuffle optimization, skew handling |
| Streaming Patterns | references/streaming-patterns.md |
Structured Streaming, watermarks, stateful operations, sinks |
Code Examples
Quick-Start Mini-Pipeline (PySpark)
from pyspark.sql import SparkSession
from pyspark.sql import functions as F
from pyspark.sql.types import StructType, StructField, StringType, LongType, DoubleType
spark = SparkSession.builder \
.appName("example-pipeline") \
.config("spark.sql.shuffle.partitions", "400") \
.config("spark.sql.adaptive.enabled", "true") \
.getOrCreate()
# Always define explicit schemas in production
schema = StructType([
StructField("user_id", StringType(), False),
StructField("event_ts", LongType(), False),
StructField("amount", DoubleType(), True),
])
df = spark.read.schema(schema).parquet("s3://bucket/events/")
result = df \
.filter(F.col("amount").isNotNull()) \
.groupBy("user_id") \
.agg(F.sum("amount").alias("total_amount"), F.count("*").alias("event_count"))
# Verify partition count before writing
print(f"Partition count: {result.rdd.getNumPartitions()}")
result.write.mode("overwrite").parquet("s3://bucket/output/")
What ships with it
5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 10d ago First seen · 151 lines · 75 tokens per session scan A 5766658d6709
spark-engineer is a skill published in the GitHub repository Jeffallan/claude-skills (11,380 stars, last pushed 1mo ago), licensed MIT. It adds 75 tokens to every session and 1,476 once invoked, about $0.0004 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.
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