# ContextVeil

> A local CLI tool that intercepts coding agent context and replaces enrolled secret values with placeholders before they reach the LLM, without blocking workflows.

ContextVeil is a free, open-source CLI tool written in Rust that prevents accidental credential exposure when using AI coding agents. It intercepts model-bound text locally and replaces exact enrolled secret values — such as API keys, tokens, and passwords — with safe placeholders before they reach the LLM. The project is maintained by daniel-sc on GitHub under the MIT OR Apache-2.0 dual license, with no account, hosted service, or network calls required at runtime.

## What It Is

ContextVeil sits between your coding agent and the LLM, performing local exact-text replacement on model-bound output. When a coding agent reads a `.env` file or runs `printenv`, the output still flows through — but any enrolled secret value is swapped for a labeled placeholder like `<SECRET:API_TOKEN>`. The tool is deliberately narrow: it does not scan arbitrary text for secret patterns at runtime, does not block file reads or commands, and does not act as a general security boundary. It is a guardrail against accidental exposure, not a comprehensive secrets management system.

## How the Workflow Works

Setup is interactive and guided. Running `contextveil setup` walks through:

- Global secrets used across projects
- Project-specific secrets from `.env`, JSON, Java properties, npmrc, and INI files
- Coding-agent integration installation
- An offline verification step (`contextveil doctor`)

ContextVeil stores **where** to find each value (e.g., "the `API_TOKEN` environment variable" or "the `STRIPE_KEY` entry in `.env.local`") rather than copying the value itself. At runtime, it reads the current value from the enrolled source for each supported event, performs literal case-sensitive matching, and exits. There is no daemon, no persistent logging, and no telemetry.

Configuration is split between a global file at `~/.config/contextveil/config.toml` and a per-project `.contextveil.toml`. The two files are additive.

## Coding Agent Integrations

ContextVeil supports four coding agents at varying stability levels:

- **Claude Code** — Production support; replaces string values in successful tool results that Claude allows hooks to replace; fails open if the hook crashes
- **OpenAI Codex CLI** — Experimental; covers supported successful tool results; replacement becomes plain text and may lose structure
- **GitHub Copilot CLI** — Experimental; covers transformed user prompts and successful text tool results
- **OpenCode** — Experimental; covers new user text and successful standard tool output on the V1 plugin API; a detected problem stops the covered operation

All fail-open integrations (Claude, Codex, Copilot) allow the coding agent to continue with original content if the hook is bypassed, disabled, or crashes.

## Known Source Rules and Secret Discovery

During setup, ContextVeil applies a maintained vocabulary of secret-like name patterns — including terms like `token`, `secret`, `password`, `key`, `apikey`, and `clientsecret` — to automatically suggest candidates from environment variables, dotenv files, Java properties, npmrc, and INI files. It also detects credential-bearing URLs regardless of key name. Common literals (`true`, `yes`, `null`, `none`, template references like `${NAME}`) are excluded from automatic suggestions to reduce false positives. Manual enrollment is also supported for any of the covered file types.

## Platform and Security Limits

V1 supports Linux (including WSL on Windows) and macOS on x86_64 and arm64. The tool explicitly documents its boundaries:

- Only current, exact enrolled values are matched; encoded, split, hashed, or transformed variants are not detected
- Coverage applies only when the coding agent loads and honors the installed integration
- Cloud, remote, container, and company-managed agent setups require their own working installation
- Short or common enrolled values can produce false-positive replacements in ordinary text

## Update: ContextVeil 1.1.0

The latest release is v1.1.0, published on 2026-09-16, following the initial v1.0.0 stable release. The project was created in August 2026 and is under active development, with 5 open issues and recent pushes to the main branch. The changelog, specification, limitations, and architecture documents are maintained alongside the source in the repository.

## Features
- Exact-text local secret replacement before LLM context is sent
- Guided interactive setup to enroll secret sources
- Supports environment variables, .env files, JSON, Java properties, npmrc, and INI files
- Claude Code production integration via hooks
- Experimental integrations for OpenAI Codex CLI, GitHub Copilot CLI, and OpenCode
- Stores source references, not secret values
- No daemon, no network calls, no telemetry at runtime
- Per-project and global configuration files
- contextveil doctor for offline integration verification
- contextveil status for configuration inspection
- Automatic secret candidate discovery using maintained name vocabulary
- Credential-bearing URL detection
- Fail-open design for Claude, Codex, and Copilot integrations
- Supports Linux (including WSL) and macOS on x86_64 and arm64
- MIT OR Apache-2.0 dual license

## Integrations
Claude Code, OpenAI Codex CLI, GitHub Copilot CLI, OpenCode, dotenv files, Java properties files, npmrc, INI files, JSON / JSON5 files

## Platforms
WINDOWS, MACOS, LINUX, API, CLI

## Pricing
Open Source

## Version
v1.1.0

## Links
- Website: https://github.com/daniel-sc/contextveil
- Documentation: https://github.com/daniel-sc/contextveil/blob/main/docs/specification.md
- Repository: https://github.com/daniel-sc/contextveil
- EveryDev.ai: https://www.everydev.ai/tools/contextveil