data-contract-testing-with-schema-registry

data-contract-testing-with-schema-registry is a skill for Claude Code, Codex from vaquarkhan/data-engineering-agent-skills. It costs 44 tokens per session (1,012 once invoked), scanned A, original, MIT.

A guide for testing shared event data formats through a schema registry, a service that stores and checks versions of data schemas. It covers compatibility between producers and consumers as schemas change.

In plain words
What is it for?
Use it to test schema changes in CI, choose backward or forward compatibility rules, identify affected consumers, and block releases that violate shared event contracts.
Why use it?
A producer can change an event in a way that breaks applications consuming it, even when the producer's own tests pass.

Skill for Claude CodeCodex

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

Good fit Use it to test schema changes in CI, choose backward or forward compatibility rules, identify affected consumers, and block releases that violate shared event contracts.

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Install with agentmods
npx agentmods add skills/vaquarkhan/data-engineering-agent-skills/data-contract-testing-with-schema-registry
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 data-contract-testing-with-schema-registry
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 data-contract-testing-with-schema-registry

README.md
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Your own site
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agentmods 80×15 button for data-contract-testing-with-schema-registry

Your own site · 80×15
<a href="https://agentmods.dev/skills/vaquarkhan/data-engineering-agent-skills/data-contract-testing-with-schema-registry"><img src="https://agentmods.dev/badge/skills/vaquarkhan/data-engineering-agent-skills/data-contract-testing-with-schema-registry.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 44 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,012 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 $0.00044 $0.01012
Opus 5 $0.00022 $0.00506
Sonnet 5 $0.00009 $0.00202
Haiku 4.5 $0.00004 $0.00101

Measured 10d ago against content hash 6524c29fa413, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

data-contract-testing-with-schema-registry 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.

skills/data-contract-testing-with-schema-registry/SKILL.md · 95 lines

How it starts

The opening of the file, as written. The whole thing — 95 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Data Contract Testing With Schema Registry

Overview

Use this skill when contracts must be tested through registry-backed compatibility rules, not only by convention. It helps agents make event contract validation a blocking part of build and release behavior with automated testing, consumer impact analysis, and evidence-driven release gates.

When to Use

  • testing event contract changes before production release
  • validating schema compatibility as part of CI/CD pipelines
  • coordinating producer and consumer schema evolution across teams
  • enforcing registry-backed contract quality gates before deployment
  • building release evidence that proves schema safety

Do not use this when schemas are not managed through a registry or when the system has no shared event contracts.

Workflow

  1. Define the contract and compatibility target per subject. Include:

    • which schema registry subjects are in scope
    • the compatibility level required: BACKWARD, FORWARD, FULL, or TRANSITIVE variants
    • who owns the contract (producing team, platform team, or shared)
    • which consumers depend on each subject and their minimum supported version
  2. Implement contract tests in CI.

    • register the proposed schema against the registry's compatibility endpoint
    • use the registry's /compatibility API to check before merging
    • fail the build if compatibility is violated
    • produce test output showing which rules passed or failed
    • run tests against both the latest registered version and specific consumer versions
  3. Test representative producer and consumer scenarios.

    • serialize sample records with the new schema and deserialize with the old
    • verify that default values produce correct behavior for removed or added fields
    • test edge cases: null handling, enum additions, nested record changes
    • for Protobuf: test field number stability and reserved field behavior
    • for Avro: test union type evolution and logical type compatibility

Read the full file on GitHub · 95 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. 10d ago First seen · 95 lines · 44 tokens per session scan A 6524c29fa413

Subscribe to this mod's changes

data-contract-testing-with-schema-registry is a skill published in the GitHub repository vaquarkhan/data-engineering-agent-skills (44 stars, last pushed 2mo ago), licensed MIT. It adds 44 tokens to every session and 1,012 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.

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