Add PreToolUse hook blocking direct glab discussion/notes API access

Redirects agents to the glab-discussion CLI when they attempt to call
glab api .../merge_requests/*/discussions|notes or glab mr view --comments,
keeping thread IDs, resolve state, and inline diff positions in scope.

Author: fprochazka

README.md

@@ -14,7 +14,10 @@ uv tool install glab-discussion
 
 ### Claude Code plugin
 
-The repo includes a Claude Code plugin with a skill that teaches AI agents how to use `glab-discussion`.
+The repo includes a Claude Code plugin with:
+
+- a **skill** that teaches AI agents how to use `glab-discussion`
+- a **PreToolUse hook** that blocks `glab api .../discussions|notes` calls and `glab mr view --comments`, redirecting the agent to use `glab-discussion` instead. This keeps thread IDs, resolve state, and inline diff positions in scope rather than letting the agent wrangle raw API JSON.
 
 ```bash
 claude plugin marketplace add fprochazka/glab-discussion

coding-agent-plugins/claude-code/hooks/block-glab-api-discussions.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+CMD=$(jq -r '.tool_input.command // empty')
+
+if [ -z "$CMD" ]; then
+  exit 0
+fi
+
+REASON="Reading or writing MR discussions/notes via \`glab\` is blocked (matched: \`glab api .../discussions|notes\` or \`glab mr view --comments\`). Use the \`glab-discussion\` CLI instead: \`glab-discussion read|write|diff|resolve|edit|delete\`. Run \`glab-discussion --help\` for usage, or load the \`glab-discussion\` skill."
+
+if printf '%s' "$CMD" | grep -qE 'glab[[:space:]]+api\b.*merge_requests[^"'"'"']*/(discussions|notes)' \
+  || printf '%s' "$CMD" | grep -qE 'glab[[:space:]]+mr[[:space:]]+view\b.*--comments\b'; then
+  jq -n --arg reason "$REASON" '{
+    hookSpecificOutput: {
+      hookEventName: "PreToolUse",
+      permissionDecision: "deny",
+      permissionDecisionReason: $reason
+    }
+  }'
+fi
+
+exit 0

coding-agent-plugins/claude-code/hooks/hooks.json

@@ -0,0 +1,16 @@
+{
+  "hooks": {
+    "PreToolUse": [
+      {
+        "matcher": "Bash",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "${CLAUDE_PLUGIN_ROOT}/hooks/block-glab-api-discussions.sh",
+            "timeout": 10
+          }
+        ]
+      }
+    ]
+  }
+}