Function toolMatchesRule

src/utils/permissions/permissions.ts:238–269

* Check if the entire tool matches a rule * For example, this matches "Bash" but not "Bash(prefix:*)" for BashTool * This also matches MCP tools with a server name, e.g. the rule "mcp__server1"

(
  tool: Pick<Tool, 'name' | 'mcpInfo'>,
  rule: PermissionRule,
)

 * This also matches MCP tools with a server name, e.g. the rule "mcp__server1"
 */
function toolMatchesRule(
  tool: Pick<Tool, 'name' | 'mcpInfo'>,
  rule: PermissionRule,
): boolean {
  // Rule must not have content to match the entire tool
  if (rule.ruleValue.ruleContent !== undefined) {
    return false
  }

  // MCP tools are matched by their fully qualified mcp__server__tool name. In
  // skip-prefix mode (CLAUDE_AGENT_SDK_MCP_NO_PREFIX), MCP tools have unprefixed
  // display names (e.g., "Write") that collide with builtin names; rules targeting
  // builtins should not match their MCP replacements.
  const nameForRuleMatch = getToolNameForPermissionCheck(tool)

  // Direct tool name match
  if (rule.ruleValue.toolName === nameForRuleMatch) {
    return true
  }

  // MCP server-level permission: rule "mcp__server1" matches tool "mcp__server1__tool1"
  // Also supports wildcard: rule "mcp__server1__*" matches all tools from server1
  const ruleInfo = mcpInfoFromString(rule.ruleValue.toolName)
  const toolInfo = mcpInfoFromString(nameForRuleMatch)

  return (
    ruleInfo !== null &&
    toolInfo !== null &&
    (ruleInfo.toolName === undefined || ruleInfo.toolName === '*') &&
    ruleInfo.serverName === toolInfo.serverName
  )
}

/**
 * Check if the entire tool is listed in the always allow rules