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 instructions/falcosecurity/prempti/claude-mdgit clone --depth 1 https://github.com/falcosecurity/premptiWrote 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/falcosecurity/prempti/claude-md)<a href="https://agentmods.dev/instructions/falcosecurity/prempti/claude-md"><img src="https://agentmods.dev/badge/instructions/falcosecurity/prempti/claude-md.svg" alt="Measured on agentmods" 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 | $0.09444 | $0.09444 |
| Opus 5 | $0.04722 | $0.04722 |
| Sonnet 5 | $0.01889 | $0.01889 |
| Haiku 4.5 | $0.00944 | $0.00944 |
Grade B, and why
prempti CLAUDE.md scanned grade B 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 6d 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.
Reads agent configuration directoriesmediumAgent snooping
.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.
- **No Windows Service**: the installer intentionally does not create a Windows Service. A per-user install cannot register a service without admin, and interception must run under the user's session anyway (it modifies Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
Falco does not ship pre-built macOS binaries. `installers/macos/build-falco.sh` clones Falco 0.44.0 and builds with `MINIMAL_BUILD=ON` + `-DBUILD_HTTP_OUTPUT=ON` (no gRPC, no webserver, just curl-based http_output). Sinc How it starts
The opening of the file, as written. The whole thing — 421 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md
This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
Overview
Prempti is a policy and visibility layer for AI coding agents. It intercepts tool calls (shell commands, file writes, web requests, etc.) before execution, evaluates them against Falco rules, and produces allow/deny/ask verdicts in real time. It operates entirely in user space with no elevated privileges.
It is not a sandbox or OS-level security boundary: at the hook level it only sees what the agent declares, not the runtime side effects of the resulting commands. It is a cooperative policy layer — the agent receives LLM-friendly feedback on blocked or flagged actions and adapts — meant to complement containment techniques, not replace them.
The project targets Claude Code as its primary integration on Linux, macOS, and Windows, with experimental Codex CLI support (interceptor + plugin path; installer wiring deferred). The wire envelope, broker, and plugin field schema are agent-agnostic by design — adding another agent is a new interceptor crate plus any agent-specific field decoding, not a rewrite.
Architecture
┌──────────────┐ ┌──────────────┐ ┌────────────────────────────┐
│ Coding Agent │───▶│ Interceptor │───▶│ Falco (nodriver) │
│ │ │ (hook) │ │ ┌───────────────────────┐ │
│ │◀───│ │◀───│ │ Plugin (src + extract│ │
│ │ │ │ │ │ + embedded broker) │ │
└──────────────┘ └──────────────┘ │ └───────────────────────┘ │
│ Rule Engine + Rules │
└────────────────────────────┘
Pipeline flow
- Interception — The coding agent's hook API fires before each tool call. The interceptor captures structured event data and pauses tool execution while awaiting a verdict.
- Event delivery — The interceptor sends the event to the plugin's embedded broker via Unix domain socket.
- Rule evaluation — The plugin feeds the event to Falco's rule engine via the source plugin API (
next_batch). Falco evaluates all loaded rules. - Alert feedback — Matching rules generate alerts. Falco delivers them back to the plugin's embedded broker via
http_output(localhost). - Verdict resolution — The broker determines the verdict from rule tags (
deny,ask, or the no-match floorallow/deferperdefault_action) and responds to the interceptor. - Verdict delivery — The interceptor communicates the verdict to the coding agent using the standard hook response format.
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.
- 6d ago First seen · 421 lines · 9,444 tokens per session scan B 2d617fb89a97
prempti CLAUDE.md is an instructions file published in the GitHub repository falcosecurity/prempti (204 stars, last pushed 4d ago), licensed Apache-2.0. It adds 9,444 tokens to every session, about $0.0472 per session on Opus 5. A static security scan graded it B with 2 findings (reads agent configuration directories, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other instructions, from other repositories
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vscode oss-third-party-notices.instructions.md
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