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 agentmods add skills/metaschema-framework/claude-plugins/using-metaschema-javanpx skills add metaschema-framework/claude-plugins --skill using-metaschema-javagit clone --depth 1 https://github.com/metaschema-framework/claude-pluginsWhat 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 | $0.00022 | $0.00511 |
| Opus 5 | $0.00011 | $0.00255 |
| Sonnet 5 | $0.00004 | $0.00102 |
| Haiku 4.5 | $0.00002 | $0.00051 |
Grade A, and why
using-metaschema-java 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 2d 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.
How it starts
The opening of the file, as written. The whole thing — 81 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Using metaschema-java CLI
The metaschema-java CLI provides command-line tools for working with Metaschema modules.
→ For programmatic Java usage: See metaschema-java-library skill
Common Commands
Validate a Metaschema Module
metaschema-cli validate <metaschema-file>
Validates the Metaschema module syntax and structure.
Validate Content Against a Metaschema
metaschema-cli validate-content --metaschema <metaschema-file> <content-file>
Validates XML or JSON content against the constraints defined in a Metaschema module.
Generate XML Schema
metaschema-cli generate-schema --as xml <metaschema-file>
Generate JSON Schema
metaschema-cli generate-schema --as json <metaschema-file>
Convert Content Between Formats
metaschema-cli convert --metaschema <metaschema-file> --to xml <json-file>
metaschema-cli convert --metaschema <metaschema-file> --to json <xml-file>
Converts content between XML and JSON formats using the Metaschema as the model definition.
Common Options
| Option | Description |
|---|---|
--as <format> |
Specify output format (xml, json) |
-o <file> |
Write output to file |
--help |
Show command help |
Best Practices
- Always validate Metaschema modules before generating schemas
- Validate content against Metaschema constraints, not just schema
- Use
--helpon any command to see available options
Troubleshooting
| Issue | Solution |
|---|---|
| Validation errors | Check module imports and namespace declarations |
| Content validation failures | Review constraint violations in output |
| Schema generation issues | Verify all referenced modules are accessible |
| Conversion errors | Ensure source content is valid before converting |
Related Skills
| Task | Skill |
|---|---|
| CLI commands (you are here) | using-metaschema-java |
| Java library/API usage | metaschema-java-library |
| Understanding Metaschema | metaschema-basics (from metaschema plugin) |
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.
- 2d ago First seen · 81 lines · 22 tokens per session scan A ae9abda57578
using-metaschema-java is a skill published in the GitHub repository metaschema-framework/claude-plugins (10 stars, last pushed 6mo ago), licensed CC0-1.0. It adds 22 tokens to every session and 511 once invoked, about $0.0001 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 2026-08-31.
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