xpia

A security command for defending against cross-prompt injection attacks, where untrusted text tries to change an agent’s instructions.

In plain words
What is it for?
Use it to handle prompt-injection defenses and related security management.
Why use it?
It helps manage a risk that can cause an agent to follow instructions hidden in external content.

Command for Claude Code

Part of the amplihack plugin — 11 skills, 45 commands, 1 agent, 6 hooks shipped together

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.

agentmods
npx agentmods add commands/rysweet/amplihack/xpia
Clone the repo
git clone --depth 1 https://github.com/rysweet/amplihack

Made for: Claude Code.

Or install amplihack, the plugin that ships this one along with the rest of its 11 skills, 45 commands, 1 agent, 6 hooks.

Per session 12 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,155 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 2 findings. Scan, not verified.
Origin unknown 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 $0.00012 $0.01155
Opus 5 $0.00006 $0.00577
Sonnet 5 $0.00002 $0.00231
Haiku 4.5 $0.00001 $0.00115

Measured 3d ago against content hash d44bcb9d54bd, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

xpia scanned grade A with 2 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 3d 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.

Asks for rootlowPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

chmod 755 ~/.claude/logs/xpia

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Reads agent configuration directorieslowAgent snooping

.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.

XPIA security level can be configured in `~/.claude/config/xpia_security.yaml`:

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

.claude/commands/amplihack/xpia.md · 192 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. 3d ago First seen · 192 lines · 12 tokens per session scan A d44bcb9d54bd

Subscribe to this mod's changes

xpia is a command published in the GitHub repository rysweet/amplihack (77 stars, last pushed 1mo ago), with no licence file. It adds 12 tokens to every session and 1,155 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 2 findings (asks for root, reads agent configuration directories). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.