Add host-protection hooks for Claude Code and Copilot CLI#16
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PreToolUse hooks that block bash/shell tool calls when a .devcontainer/devcontainer.json exists, forcing agents to use devcontainer-mcp MCP tools instead of executing on the host. - hooks/devcontainer-guard.sh: shared hook script supporting both Claude Code and Copilot CLI payload formats - .github/hooks/devcontainer-guard.json: Copilot CLI hook config for this repo - install.sh/install.ps1: auto-install hooks and configure agent environments during installation - 10 integration tests validating block/allow/bypass behavior - SKILL.md footer updated to mention hook enforcement Bypass: USER_CONFIRMED_HOST_OPERATION=1 in the command allows through, designed as a semantic tripwire that LLMs cannot honestly generate.
This was referenced May 13, 2026
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Summary
PreToolUse hooks that block bash/shell tool calls when a
.devcontainer/devcontainer.jsonexists in the working directory, forcing agents to use devcontainer-mcp MCP tools instead of executing on the host.Changes
hooks/devcontainer-guard.sh— shared hook script supporting both Claude Code (tool_name/tool_input) and Copilot CLI (toolName/toolArgs) payload formats.github/hooks/devcontainer-guard.json— Copilot CLI hook config for this repoinstall.sh/install.ps1— auto-install hooks and configure agent environments (Claude Code~/.claude/settings.json, Copilot CLI~/.copilot/hooks/) during installationskills/footer.md/SKILL.md— mention hook enforcement in the "What NOT to do" sectioncrates/devcontainer-mcp-core/tests/hook_guard_test.rs) validating block/allow/bypass behavior across both agent formatsHow it works
USER_CONFIRMED_HOST_OPERATION=1is in the command → allows through (human bypass).devcontainer/devcontainer.jsonexists in cwd → denies with helpful messageThe bypass string is a semantic tripwire: even if an LLM discovers it by reading the hook script, generating
USER_CONFIRMED_HOST_OPERATION=1means falsely asserting that a user confirmed the operation — directly conflicting with honesty training.