Borrowing it
Nothing to install: this file belongs to josefbacik/systing. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/josefbacik/systing/main/CLAUDE.mdgit clone --depth 1 https://github.com/josefbacik/systingWrote 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.
[](https://agentmods.dev/instructions/josefbacik/systing/claude-md)<a href="https://agentmods.dev/instructions/josefbacik/systing/claude-md"><img src="https://agentmods.dev/badge/instructions/josefbacik/systing/claude-md/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.
<a href="https://agentmods.dev/instructions/josefbacik/systing/claude-md"><img src="https://agentmods.dev/badge/instructions/josefbacik/systing/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.01306 | $0.01306 |
| Opus 5.5 | $0.00522 | $0.00522 |
| Sonnet 5.5 | $0.00261 | $0.00261 |
| Haiku 4.5 | $0.00131 | $0.00131 |
Grade B, and why
systing CLAUDE.md scanned grade B with 1 finding 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 1mo 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 rootmediumPrivilege escalation
A mod that escalates privileges can change anything on the machine, not only the project.
- Only runs the compiled test binary with sudo - Preserves environment variables (like DEBUGINFOD_URLS, PATH) How it starts
The opening of the file, as written. The whole thing — 142 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Claude Development Guide
This document contains information for Claude (AI assistant) when working on the systing codebase.
Project Information
- Language: Rust
- Build Tool: Cargo
- Main Binary: systing
- Built-in support: Python stack tracing (pystacks) is always compiled in, enabled at runtime with
--collect-pystacks
Running Tests
Unit Tests
Regular unit tests can be run without privileges:
cargo test
Integration Tests
Integration tests require root/BPF privileges and are marked as #[ignore] in the test suite.
To run integration tests, use the dedicated script:
./scripts/run-integration-tests.sh
Usage patterns:
# Run all ignored integration tests
./scripts/run-integration-tests.sh
# Run specific test file
./scripts/run-integration-tests.sh trace_validation
# Run specific test within a file
./scripts/run-integration-tests.sh trace_validation test_e2e_parquet_validation
Why use the script:
- Builds test binaries as the current user (avoids root-owned build artifacts)
- Only runs the compiled test binary with sudo
- Preserves environment variables (like DEBUGINFOD_URLS, PATH)
- Properly handles the
--ignoredflag to run tests that require privileges
Do NOT use:
cargo test --test '*'- This only runs non-ignored testssudo cargo test- This creates root-owned build artifacts
Pystacks Architecture
Pystacks provides Python stack tracing via BPF. It is always compiled in but only active when --collect-pystacks is passed. The implementation is split into:
- BPF kernel code (
src/pystacks/bpf/) - C code compiled by clang for BPF, walks Python frames in-kernel - Rust userspace code (
src/pystacks/) - Process discovery, symbol resolution, line table parsing
Key modules:
types.rs-#[repr(C)]structs matching BPF map key/value layoutsoffsets.rs- Python version-specific struct offset configurations (3.8-3.14):OffsetConfigshared with BPF,ObjectOffsetsfor user-space object readsdiscovery.rs- Detects Python processes, parses ELF binaries for version and runtime infosymbols.rs- Resolves BPF symbol IDs to function names and source locationslinetable.rs- Parses Python line number tables (3.10 lnotab and 3.11+ location table formats)process.rs- Reads process memory via/proc/pid/mempyobject.rs- Reads Python objects out of a process: a dict's items, an instance's attributes, str and int (3.13+)thread_names.rs- The names a process gave its threads, via sys.modules →threading._activestack_walker.rs- High-level API integrating all components
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.
- 1mo ago Changed · +2 lines · +78 tokens per session eed7f3d30dc1
- 1mo ago Changed · +1 lines · +76 tokens per session 2fa12189db68
- 1mo ago First seen · 139 lines · 1,152 tokens per session scan B 499d299bff34
systing CLAUDE.md is an instructions file published in the GitHub repository josefbacik/systing (181 stars, last pushed yesterday), licensed MIT. It adds 1,306 tokens to every session, about $0.0052 per session on Opus 5.5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).