permissions hook helper
Add allow-last, deny-last, and review commands for fast rule feedback loop
+176
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+176
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chook.mjs
+176
-21
chook.mjs
···
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};
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}
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// --- TOML generation ---
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// Escape a string for TOML double-quoted value
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function tomlEscape(s) {
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return s.replace(/\\/g, "\\\\").replace(/"/g, '\\"');
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}
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// Escape a string to be a safe regex literal
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function regexEscape(s) {
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return s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
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}
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// Build a TOML rule block from an audit entry
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function buildRuleFromEntry(entry, ruleType) {
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const lines = [`[[${ruleType}]]`, `tool = "${entry.tool_name}"`];
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const toolInput = entry.tool_input;
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switch (entry.tool_name) {
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case "Read":
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case "Write":
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case "Edit":
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case "MultiEdit":
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case "Glob":
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case "NotebookEdit": {
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const filePath = toolInput.file_path || toolInput.notebook_path;
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if (filePath) {
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lines.push(`file_path_regex = "${tomlEscape(regexEscape(filePath))}"`);
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}
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break;
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}
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case "Bash": {
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const cmd = toolInput.command;
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if (cmd) {
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// Use the first word(s) as a prefix pattern rather than the full command
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const prefix = cmd.split(/\s+/).slice(0, 2).join(" ");
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lines.push(`command_regex = "^${tomlEscape(regexEscape(prefix))}"`);
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}
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break;
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}
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case "Task": {
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if (toolInput.subagent_type) {
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lines.push(`subagent_type = "${tomlEscape(toolInput.subagent_type)}"`);
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}
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break;
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}
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}
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return lines.join("\n");
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}
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// Append a rule block to the config file
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function appendRuleToConfig(configPath, ruleBlock) {
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appendFileSync(configPath, "\n" + ruleBlock + "\n");
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}
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// --- Audit reading ---
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function readAuditEntries(auditPath, filter) {
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let text;
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try {
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text = readFileSync(auditPath, "utf-8").trim();
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} catch {
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return [];
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}
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if (!text) return [];
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let entries = text.split("\n").map((line) => JSON.parse(line));
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if (filter) {
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entries = entries.filter((e) => filter.includes(e.decision));
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}
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return entries;
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}
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function formatEntry(entry, idx) {
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const time = entry.timestamp.replace("T", " ").replace(/\.\d+Z$/, "Z");
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const tool = entry.tool_name;
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const decision = entry.decision.toUpperCase();
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let detail = "";
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switch (tool) {
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case "Bash":
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detail = entry.tool_input.command || "";
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break;
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case "Read":
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case "Write":
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case "Edit":
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case "MultiEdit":
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case "Glob":
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case "NotebookEdit":
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detail = entry.tool_input.file_path || entry.tool_input.notebook_path || "";
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break;
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case "Task":
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detail = entry.tool_input.subagent_type || "";
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break;
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default:
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detail = JSON.stringify(entry.tool_input).slice(0, 80);
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}
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// Truncate detail for display
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if (detail.length > 80) detail = detail.slice(0, 77) + "...";
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return ` ${String(idx).padStart(3)} ${decision.padEnd(11)} ${tool.padEnd(12)} ${detail} [${time}]`;
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}
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// --- CLI ---
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const args = process.argv.slice(2);
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const command = args[0];
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if (command === "validate") {
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const configIdx = args.indexOf("--config");
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const configPath = configIdx >= 0 ? args[configIdx + 1] : null;
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if (!configPath) {
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console.error("Usage: chook validate --config <path>");
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function getConfigPath() {
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const idx = args.indexOf("--config");
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return idx >= 0 ? resolve(args[idx + 1]) : null;
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}
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function getRequiredConfigPath() {
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const p = getConfigPath();
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if (!p) {
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console.error("Missing --config <path>");
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process.exit(1);
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}
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return p;
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}
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if (command === "validate") {
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const configPath = getRequiredConfigPath();
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try {
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const config = loadConfig(resolve(configPath));
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const config = loadConfig(configPath);
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const denyRules = compileRules(config.deny || []);
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const allowRules = compileRules(config.allow || []);
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console.log("Configuration is valid!");
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process.exit(1);
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}
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} else if (command === "run") {
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const configIdx = args.indexOf("--config");
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const configPath = configIdx >= 0 ? args[configIdx + 1] : null;
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if (!configPath) {
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console.error("Usage: chook run --config <path>");
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process.exit(1);
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}
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const configPath = getRequiredConfigPath();
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try {
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const config = loadConfig(resolve(configPath));
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const config = loadConfig(configPath);
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const denyRules = compileRules(config.deny || []);
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const allowRules = compileRules(config.allow || []);
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// Read JSON from stdin
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const stdin = readFileSync(0, "utf-8");
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const input = JSON.parse(stdin);
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···
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const toolInput = input.tool_input;
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const cwd = input.cwd;
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// Check deny first
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const denyReason = checkRules(denyRules, toolName, toolInput, cwd);
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if (denyReason) {
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audit(config.audit, input, "deny", denyReason);
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process.exit(0);
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}
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// Check allow
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const allowReason = checkRules(allowRules, toolName, toolInput, cwd);
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if (allowReason) {
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audit(config.audit, input, "allow", allowReason);
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process.exit(0);
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}
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// Passthrough - no output
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audit(config.audit, input, "passthrough", null);
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} catch (e) {
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process.stderr.write(`chook error: ${e.message}\n`);
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process.exit(1);
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}
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} else if (command === "allow-last" || command === "deny-last") {
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const configPath = getRequiredConfigPath();
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const ruleType = command === "allow-last" ? "allow" : "deny";
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const config = loadConfig(configPath);
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const auditPath = config.audit?.audit_file;
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if (!auditPath) {
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console.error("No audit_file configured — can't read last entry.");
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process.exit(1);
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}
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const entries = readAuditEntries(auditPath);
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if (entries.length === 0) {
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console.error("Audit log is empty.");
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process.exit(1);
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}
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const last = entries[entries.length - 1];
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const ruleBlock = buildRuleFromEntry(last, ruleType);
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console.log(`Adding ${ruleType} rule from last audit entry:\n`);
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console.log(ruleBlock);
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console.log(`\n-> Appended to ${configPath}`);
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appendRuleToConfig(configPath, ruleBlock);
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} else if (command === "review") {
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const configPath = getRequiredConfigPath();
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const config = loadConfig(configPath);
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const auditPath = config.audit?.audit_file;
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if (!auditPath) {
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console.error("No audit_file configured.");
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process.exit(1);
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}
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// Show deny and passthrough entries (things that weren't auto-allowed)
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const entries = readAuditEntries(auditPath, ["deny", "passthrough"]);
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if (entries.length === 0) {
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console.log("No deny/passthrough entries in audit log.");
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process.exit(0);
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}
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// Deduplicate by tool+detail to show unique patterns
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const seen = new Set();
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const unique = [];
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for (const entry of entries) {
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const ti = entry.tool_input;
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const key = entry.tool_name + ":" + (ti.command || ti.file_path || ti.notebook_path || ti.subagent_type || "");
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if (!seen.has(key)) {
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seen.add(key);
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unique.push(entry);
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}
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}
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console.log(`Denied/passthrough entries (${unique.length} unique):\n`);
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console.log(" IDX DECISION TOOL DETAIL");
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console.log(" --- -------- ---- ------");
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unique.forEach((e, i) => console.log(formatEntry(e, i)));
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console.log(`\nTo add a rule, run:`);
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console.log(` chook allow-last --config ${configPath} # allow the most recent entry`);
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console.log(` chook deny-last --config ${configPath} # deny the most recent entry`);
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console.log(`\nOr edit ${configPath} directly for more control.`);
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} else {
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console.error("Usage: chook <run|validate> --config <path>");
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console.error("Usage: chook <command> --config <path>");
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console.error("");
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console.error("Commands:");
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console.error(" run Run as PreToolUse hook (reads JSON from stdin)");
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console.error(" validate Validate a TOML configuration file");
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console.error(" run Run as PreToolUse hook (reads JSON from stdin)");
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console.error(" validate Validate a TOML configuration file");
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console.error(" allow-last Add an allow rule from the last audit entry");
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console.error(" deny-last Add a deny rule from the last audit entry");
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console.error(" review Show denied/passthrough entries from the audit log");
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process.exit(1);
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}