What is metaschema-java-library?

A guide to the metaschema-java library, a Java framework for loading Metaschema modules, reading and writing XML or JSON, evaluating expressions, and validating constraints. It also describes the library’s main modules and interfaces.

Use it when implementing or reviewing Metaschema Java code, including data binding, expression evaluation, constraint validation, and serialization.

It reduces the need to discover the library’s APIs and module structure from source code alone.

metaschema-java-library — Skill by metaschema-framework/claude-plugins

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 metaschema-framework/claude-plugins --skill metaschema-java-library

Clone the repo

git clone --depth 1 https://github.com/metaschema-framework/claude-plugins

Made for: Claude Code.

Or install metaschema-tools, the plugin that ships this one along with the rest of its 2 skills.

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/metaschema-framework/claude-plugins/metaschema-java-library/github.svg)](https://agentmods.dev/skills/metaschema-framework/claude-plugins/metaschema-java-library)

Your own site

<a href="https://agentmods.dev/skills/metaschema-framework/claude-plugins/metaschema-java-library"><img src="https://agentmods.dev/badge/skills/metaschema-framework/claude-plugins/metaschema-java-library/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/metaschema-framework/claude-plugins/metaschema-java-library"><img src="https://agentmods.dev/badge/skills/metaschema-framework/claude-plugins/metaschema-java-library.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 35 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 4,766 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	$0.00035	$0.04766
Opus 5.5	$0.00014	$0.01906
Sonnet 5.5	$0.00007	$0.00953
Haiku 4.5	$0.00003	$0.00477

Measured 2mo ago against content hash fecfea4230b9, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

metaschema-java-library 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 2mo 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.

plugins/metaschema-tools/skills/metaschema-java-library/SKILL.md · 691 lines

How it starts

The opening of the file, as written. The whole thing — 691 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Using the metaschema-java Library

This skill covers how to use the metaschema-java library for loading modules, evaluating Metapath expressions, validating constraints, and serializing/deserializing data.

Related skills from the metaschema plugin (install with claude plugin install metaschema-framework:metaschema):

metaschema-module-authoring - Module structure, definitions, data types
metaschema-constraints-authoring - Constraint types and validation patterns
metapath-expressions - Metapath syntax, operators, and functions

Module Structure

metaschema-framework (parent)
├── core                    - Core API, Metapath engine, model interfaces
├── databind                - Data binding, serialization, code generation
├── schemagen               - XML/JSON schema generation
├── databind-modules        - Metaschema binding modules
├── metaschema-maven-plugin - Maven plugin for code/schema generation
├── metaschema-testing      - Testing utilities
├── cli-processor           - CLI framework
└── metaschema-cli          - Command-line interface

Key Packages

Package	Purpose
`dev.metaschema.core.model`	Model interfaces (`IModule`, `IAssemblyDefinition`, etc.)
`dev.metaschema.core.metapath`	Metapath expression engine
`dev.metaschema.core.metapath.function`	Function library
`dev.metaschema.core.metapath.item`	Item types (nodes, atomics)
`dev.metaschema.core.model.constraint`	Constraint validation
`dev.metaschema.databind`	Data binding context
`dev.metaschema.databind.io`	Serialization/deserialization
`dev.metaschema.databind.model.annotations`	Binding annotations (`@BoundField`, `@BoundChoice`, etc.)
`dev.metaschema.databind.codegen`	Code generation from Metaschema modules

Annotation-Based Binding Model

The databind module provides annotation-based bindings that map Java classes to Metaschema definitions.

Core Binding Annotations

Annotation	Purpose
`@MetaschemaAssembly`	Marks a class as a bound assembly definition
`@MetaschemaField`	Marks a class as a bound field definition
`@BoundAssembly`	Marks a field as a bound assembly instance
`@BoundField`	Marks a field as a bound field instance
`@BoundFlag`	Marks a field as a bound flag instance
`@BoundChoice`	Marks a field as part of a mutually exclusive choice
`@BoundChoiceGroup`	Marks a field as a polymorphic collection with discriminator

Read the full file on GitHub · 691 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.

2mo ago First seen · 691 lines · 35 tokens per session scan A fecfea4230b9

Subscribe to this mod's changes

metaschema-java-library is a skill published in the GitHub repository metaschema-framework/claude-plugins (10 stars, last pushed 8mo ago), licensed CC0-1.0. It adds 35 tokens to every session and 4,766 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 2026-08-31.

Java Languages

metaschema-java-library next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
metaschema-java-librarymetaschema-framework/claude-plugins	Skill	10	8mo ago	CC0-1.0	A	35	Claude Code
java-affected-testsopen-metadata/OpenMetadata	Skill	16k	today	Apache-2.0	A	120	Claude Code
azure-communication-chat-javamicrosoft/skills	Skill	3.2k	today	MIT	A	41	Claude Code
azure-communication-common-javamicrosoft/skills	Skill	3.2k	today	MIT	A	35	Claude Code
azure-security-keyvault-secrets-javamicrosoft/skills	Skill	3.2k	today	MIT	A	40	Claude Code
azure-ai-anomalydetector-javamicrosoft/skills	Skill	3.2k	today	MIT	A	43	Claude Code
azure-ai-agents-persistent-javamicrosoft/skills	Skill	3.2k	today	MIT	A	63	Claude Code