stub-interposition

stub-interposition is a skill for Claude Code, Codex from Jiusi-pys/agent-plugins. It costs 54 tokens per session (1,383 once invoked), scanned A, original, no licence file.

A testing technique that replaces selected runtime functions without changing source code or rebuilding the program. It uses the Linux LDPRELOAD mechanism to intercept dynamically linked functions and record behavior such as input/output and system calls.

In plain words
What is it for?
Adding test instrumentation to existing programs and recording input/output, system calls, and memory operations.
Why use it?
It lets developers observe or replace behavior in tests when modifying and recompiling the original code is not practical.

Skill for Claude CodeCodex

Part of the ohos-porting plugin — 14 skills, 4 commands, 7 agents 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 skills/jiusi-pys/agent-plugins/stub-interposition
Any agent
npx skills add Jiusi-pys/agent-plugins --skill stub-interposition
Clone the repo
git clone --depth 1 https://github.com/Jiusi-pys/agent-plugins

Made for: Claude Code, Codex.

Or install ohos-porting, the plugin that ships this one along with the rest of its 14 skills, 4 commands, 7 agents.

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 stub-interposition

README.md
[![agentmods](https://agentmods.dev/badge/skills/jiusi-pys/agent-plugins/stub-interposition.svg)](https://agentmods.dev/skills/jiusi-pys/agent-plugins/stub-interposition)
Your own site
<a href="https://agentmods.dev/skills/jiusi-pys/agent-plugins/stub-interposition"><img src="https://agentmods.dev/badge/skills/jiusi-pys/agent-plugins/stub-interposition.svg" alt="Measured on agentmods" height="20"></a>
Per session 54 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,383 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 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 $0.00054 $0.01383
Opus 5 $0.00027 $0.00691
Sonnet 5 $0.00011 $0.00277
Haiku 4.5 $0.00005 $0.00138

Measured 3d ago against content hash ca112ad2c209, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

stub-interposition 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 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.

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/ohos-porting/skills/stub-interposition/SKILL.md · 164 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

Files

What ships with it

4 files 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.

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 · 164 lines · 54 tokens per session scan A ca112ad2c209

Subscribe to this mod's changes

stub-interposition is a skill published in the GitHub repository Jiusi-pys/agent-plugins (1 stars, last pushed 2mo ago), with no licence file. It adds 54 tokens to every session and 1,383 once invoked, about $0.0003 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.