From f4c7e1a37ff5bae400badf8a0ff26ce98444ea48 Mon Sep 17 00:00:00 2001
From: Amit Vijapur <vijapuramit@gmail.com>
Date: Tue, 21 Jul 2026 00:38:00 +0800
Subject: [PATCH] fix(hooks): read PostToolUse payload from stdin instead of
 $TOOL_INPUT env var
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The PostToolUse auto-update hook read "$TOOL_INPUT" to detect git
commit/merge/cherry-pick/rebase commands, but Claude Code never sets a
TOOL_INPUT environment variable for hook processes — hook input is
delivered as JSON on stdin (fields tool_name, tool_input, cwd, ...).
The grep therefore always tested an empty string, the && chain
short-circuited, and the trailing || true swallowed the failure: the
per-commit auto-update silently never fired, on any OS.

Capture stdin into INPUT, then extract tool_input.command via a small
node -e script (matching the JSON-parsing style already used by the
SessionStart hook's node -p call, and requiring no new dependency —
jq isn't guaranteed present on Windows/Git Bash hosts). The extracted
command is piped into the same grep check as before; everything
downstream (UA_DIR resolution, config.json/knowledge-graph.json gating)
is unchanged.

Verified by piping a realistic PostToolUse JSON payload into both the
old and new hook commands: the old command produces no output (bug
reproduced), the new one prints the auto-update instruction. Also
checked git merge/cherry-pick/rebase trigger correctly, non-matching
commands and non-Bash tool payloads (no tool_input.command field) stay
silent, embedded quotes in commit messages don't break JSON parsing,
and the autoUpdate:false / missing knowledge-graph.json gates still
suppress the hook as before.

Fixes #594.
---
 understand-anything-plugin/hooks/hooks.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/understand-anything-plugin/hooks/hooks.json b/understand-anything-plugin/hooks/hooks.json
index 3daa83fb8..de9bb14e8 100644
--- a/understand-anything-plugin/hooks/hooks.json
+++ b/understand-anything-plugin/hooks/hooks.json
@@ -6,7 +6,7 @@
         "hooks": [
           {
             "type": "command",
-            "command": "UA_DIR=.understand-anything; [ -d \"$UA_DIR\" ] || UA_DIR=.ua; printf '%s' \"$TOOL_INPUT\" | grep -qE 'git\\s+(commit|merge|cherry-pick|rebase)' && [ -f $UA_DIR/config.json ] && grep -q '\"autoUpdate\".*true' $UA_DIR/config.json && [ -f $UA_DIR/knowledge-graph.json ] && echo \"[understand-anything] Commit detected with auto-update enabled. You MUST read the file at ${CLAUDE_PLUGIN_ROOT}/hooks/auto-update-prompt.md and execute its instructions to incrementally update the knowledge graph. Do not ask the user for confirmation — just do it.\" || true"
+            "command": "UA_DIR=.understand-anything; [ -d \"$UA_DIR\" ] || UA_DIR=.ua; INPUT=$(cat); CMD=$(printf '%s' \"$INPUT\" | node -e \"let d='';process.stdin.on('data',c=>d+=c);process.stdin.on('end',()=>{try{process.stdout.write(JSON.parse(d).tool_input?.command||'')}catch{}})\" 2>/dev/null); printf '%s' \"$CMD\" | grep -qE 'git\\s+(commit|merge|cherry-pick|rebase)' && [ -f $UA_DIR/config.json ] && grep -q '\"autoUpdate\".*true' $UA_DIR/config.json && [ -f $UA_DIR/knowledge-graph.json ] && echo \"[understand-anything] Commit detected with auto-update enabled. You MUST read the file at ${CLAUDE_PLUGIN_ROOT}/hooks/auto-update-prompt.md and execute its instructions to incrementally update the knowledge graph. Do not ask the user for confirmation — just do it.\" || true"
           }
         ]
       }