Claude Code 2.1.178: Faster Search, Granular Permissions, Safer Sub-Agents

Key Takeaways

• 1. Faster search via ripgrep. Tool descriptions now recommend a ripgrep-based grep. Install ripgrep and Claude Code uses it automatically, making file searches ~5–10× faster in large projects. It respects .gitignore, so the agent skips folders that don't matter. Because every task involves dozens of background searches, this compounds across a whole session.
• 2. Granular Tool(param:value) permissions. Permission rules now accept a Tool(param:value) syntax with a * wildcard to block specific tool inputs — not just whole tools. You can allow Edit only in one folder, or block Bash commands that touch a given directory. You can also control which sub-agents spawn with Task(agent_name), and disable agents at startup with the --disallow-tools CLI flag.
• 3. Sub-agents are checked before they launch. Previously a sub-agent could be spawned before the permission system evaluated it, leaving a gap where it might bypass the parent's rules. In 2.1.178 sub-agent spawns are evaluated by the classifier before launch. Sub-agents can't show interactive permission prompts, and a blocked tool call is treated as denied. Recommended pattern: keep sub-agents read-only and defer all editing to the parent agent that can handle approvals.
• Bundled bug fixes: completed sessions now retire even when an idle sub-agent is parked or a backgrounded shell leaked; background work trees are no longer orphaned after the 30-day job-retention sweep; background sessions reattached after sleep/wake now get the correct date; sub-agents now inherit dynamically injected MCP servers; and isolated-worktree sub-agents are no longer denied read/edit access inside their own worktree.
• Why it matters: faster search + precise permissions + rule-abiding sub-agents means you can define rules once at the top level and have them hold all the way down — the reliability foundation needed to scale multi-agent workflows instead of babysitting them.

Commands & Code Mentioned

# Update Claude Code to 2.1.178
npm update @anthropic-ai/claude-code

# Granular permission rule shape (block/allow specific tool inputs)
Tool(param:value)        # with * wildcard to match a category of inputs
Task(agent_name)         # control which sub-agents can spawn

# Disable specific agents/tools at startup
claude --disallow-tools <tool-or-agent>

See our changelog for the full 2.1.176–179 release notes, and OpenClaw configuration and security for permission-rule details.