What is jvm-server-frameworks?

A development guide for building Kotlin server applications with Ktor and storing data with Exposed, a Kotlin database library. It also defines database migrations, transactions, validation, authentication, and JSON handling.

Use it to build Ktor APIs, define routes and services, query databases, run Flyway migrations, manage connection pools, and handle structured JSON data.

It provides consistent patterns for routing requests, safely changing database schemas, managing transactions, and organizing server-side code.

jvm-server-frameworks — Skill for Claude Code and Codex by jxoesneon

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 jxoesneon/Ciel --skill jvm-server-frameworks

Clone the repo

git clone --depth 1 https://github.com/jxoesneon/Ciel

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/jxoesneon/ciel/jvm-server-frameworks/github.svg)](https://agentmods.dev/skills/jxoesneon/ciel/jvm-server-frameworks)

Your own site

<a href="https://agentmods.dev/skills/jxoesneon/ciel/jvm-server-frameworks"><img src="https://agentmods.dev/badge/skills/jxoesneon/ciel/jvm-server-frameworks/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/jxoesneon/ciel/jvm-server-frameworks"><img src="https://agentmods.dev/badge/skills/jxoesneon/ciel/jvm-server-frameworks.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 24 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 415 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.

Model	Per session	Once invoked
Fable 5.1	$0.00024	$0.00415
Opus 5.5	$0.00010	$0.00166
Sonnet 5.5	$0.00005	$0.00083
Haiku 4.5	$0.00002	$0.00042

Measured 29d ago against content hash 9bfc85ae92df, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

jvm-server-frameworks 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 29d 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/jvm-server-frameworks/SKILL.md · 39 lines

What it actually says

CIEL ADAPTATION: JVM Server Frameworks (Ktor & Exposed)

This skill formalizes the use of lightweight, DSL-driven frameworks on the JVM. It focuses on the Ktor + Exposed + Flyway stack.

Ktor Server Standards

Plugin Discipline: Install ContentNegotiation, Authentication, and StatusPages in the central module.
Routing DSL: Group routes by resource (/users, /orders). Extract logic to Services injected via Koin.
Validation: Use require() blocks at the route boundary for fail-fast input checking.
Serialization: Standardize on kotlinx.serialization with custom serializers for Instant.

Exposed ORM (Persistence)

Transaction Safety: All DB operations MUST run inside newSuspendedTransaction.
DSL vs DAO:
- Use DSL style for complex joins and aggregations.
- Use DAO style for entity lifecycle and simple CRUD.
JSONB: Use the jsonb column pattern with kotlinx.serialization for unstructured metadata.

Database Lifecycle

Migrations: Mandate Flyway for all schema changes. Versioned SQL scripts only.
Connection Pooling: Use HikariCP with TRANSACTION_READ_COMMITTED isolation.

Anti-Patterns

Implicit Nulls: Allowing explicitNulls = true in serialization (leads to large, sparse JSON).
Blocking Transactions: Running long-running I/O or network calls inside a transaction block.
Manual Table Creation: Using SchemaUtils.create in production instead of Flyway.

Files

What ships with it

1 file 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.

ciel.yaml 445 B

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.

29d ago Changed · -13 lines 9bfc85ae92df
1mo ago First seen · 52 lines · 24 tokens per session scan A 5b3075c9d9f7

Subscribe to this mod's changes

jvm-server-frameworks is a skill published in the GitHub repository jxoesneon/Ciel (1 stars, last pushed today), licensed Apache-2.0. It adds 24 tokens to every session and 415 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-09-03.

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