Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add slbug/claude-ruby-grape-rails/plugin install ruby-grape-railsWrote 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/hooks/slbug/claude-ruby-grape-rails/post-tool-use-failure)<a href="https://agentmods.dev/hooks/slbug/claude-ruby-grape-rails/post-tool-use-failure"><img src="https://agentmods.dev/badge/hooks/slbug/claude-ruby-grape-rails/post-tool-use-failure.svg" alt="Measured on agentmods" height="20"></a>Grade A, and why
PostToolUseFailure 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 4d ago.
A static scan of the commands this hook runs, not an audit. A hook is shell that executes on your machine at the event it names, which is why every command in it is printed with what was found.
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.
How it starts
The opening of the file, as written. The whole thing — 146 lines — stays where its author put it; the contents beside it link to each section on GitHub.
{
"PostToolUseFailure": [
{
"matcher": "Bash",
"hooks": [
{
"type": "command",
"if": "Bash(bundle *)",
"command": "${CLAUDE_PLUGIN_ROOT}/hooks/scripts/ruby-post-tool-use-failure.sh",
"timeout": 30
},
{
"type": "command",
"if": "Bash(rails *)",
"command": "${CLAUDE_PLUGIN_ROOT}/hooks/scripts/ruby-post-tool-use-failure.sh",
"timeout": 30
},
{
"type": "command",
"if": "Bash(bin/rails *)",
"command": "${CLAUDE_PLUGIN_ROOT}/hooks/scripts/ruby-post-tool-use-failure.sh",
"timeout": 30
},
{
"type": "command",
"if": "Bash(./bin/rails *)",
"command": "${CLAUDE_PLUGIN_ROOT}/hooks/scripts/ruby-post-tool-use-failure.sh",
"timeout": 30
},
{
"type": "command",
"if": "Bash(rake *)",
"command": "${CLAUDE_PLUGIN_ROOT}/hooks/scripts/ruby-post-tool-use-failure.sh",
"timeout": 30
},
{
"type": "command",
"if": "Bash(bin/rake *)",
"command": "${CLAUDE_PLUGIN_ROOT}/hooks/scripts/ruby-post-tool-use-failure.sh",
"timeout": 30
},
{
"type": "command",
"if": "Bash(./bin/rake *)",
"command": "${CLAUDE_PLUGIN_ROOT}/hooks/scripts/ruby-post-tool-use-failure.sh",
"timeout": 30
},
{
"type": "command",
"if": "Bash(ruby *)",
"command": "${CLAUDE_PLUGIN_ROOT}/hooks/scripts/ruby-post-tool-use-failure.sh",
"timeout": 30
},
{
"type": "command",
"if": "Bash(rspec *)",
"command": "${CLAUDE_PLUGIN_ROOT}/hooks/scripts/ruby-post-tool-use-failure.sh",
"timeout": 30
},
{
"type": "command",
"if": "Bash(bin/rspec *)",
"command": "${CLAUDE_PLUGIN_ROOT}/hooks/scripts/What else hooks.json configures
This page is one entry in a file that holds 17. Installing the file brings all of them; each is measured and scanned on its own page.
- Hook CwdChanged A not measured
- Hook DirectoryAdded A not measured
- Hook FileChanged A not measured
- Hook PermissionDenied A not measured
- Hook PermissionRequest A not measured
- Hook PostCompact A not measured
- Hook PostToolBatch A not measured
- Hook PostToolUse A not measured
- Hook PreCompact A not measured
- Hook PreToolUse A not measured
- Hook SessionStart A not measured
- Hook Stop A not measured
- Hook StopFailure A not measured
- Hook SubagentStart A not measured
- Hook UserPromptExpansion A not measured
- Hook UserPromptSubmit A not measured
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.
- 4d ago First seen · 146 lines scan A 3f8a14be5960
PostToolUseFailure is a hook published in the GitHub repository slbug/claude-ruby-grape-rails (7 stars, last pushed 4d ago), licensed MIT. Its token cost is not measured: a hook is shell that never enters the context. 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.
Other hooks, from other repositories
UserPromptSubmit
Runs when you submit a prompt, before the agent sees it, executing pipeline-prompt.sh. From Pierry/harness-kit.
Stop
Runs when the agent finishes a response, executing dejavu-hook.py via python. From HthSolid/claude-dejavu.
PreToolUse
Runs before the agent uses a tool for Bash, shell_command, exec_command, unified_exec, apply_patch, Write and Edit tool calls, executing pre-tool-adapter.py via python3 (2 commands). From arbiterForge/codeArbiter.
PostToolUse
Runs after a tool call finishes for Write and Edit tool calls, executing format_and_lint.sh. From supabase/supabase.
SessionStart
Runs when a session starts, executing on-start.js via node. From google-gemini/gemini-cli.
SessionStart
Runs when a session starts on startup, executing install_pkgs.sh. From supabase/supabase.