Claude Code v2.1.178 gives you parameter-level permissions and gates subagent spawns before launch

The June 15 release of Claude Code (v2.1.178) is small on the changelog and large in practice. Two changes matter for anyone running agentic workflows daily.

First, permission rules now match on parameters, not just tool names. You can write Agent(model:opus) to block Opus subagents specifically, with wildcard support. Before this, your permission surface was coarse. You allowed a tool or you didn't. Now you can say "this agent can spawn subagents, but not expensive ones" or "this skill can call the shell, but not with these flags." That's the difference between a bouncer who checks IDs and one who only knows whether you're on the list.

Second, and this is the one I care about: improved auto mode now runs the classifier on subagent spawns before launch. Previously a subagent could request a blocked action and you'd find out after the fact. The review happened too late to prevent anything. Now the gate is in front of the door. If you've ever watched a nested agent quietly do something you'd never have approved at the top level, you know exactly which privilege gap this closes.

There's a third thing that's easy to miss. Nested .claude/skills directories now auto-load by working directory, and the closest .claude/ wins for agents, workflows, and output styles. Name clashes show up as <dir>:<name>. This is the end of the monolithic top-level skills folder. You can colocate a module's skills next to the code they govern, and context loads only where it's relevant. For a big repo, that's a real reduction in noise. The model isn't scanning forty skill descriptions to find the two that apply to the file you're editing.

It also fixed two quiet bugs: --fallback-model was being ignored during compaction, and MCP server-level specs were ignored in subagent disallowedTools. Both are the kind of thing you'd never notice until a 2am run does something off-policy and you can't reproduce it.

What to do today: audit your permission config and tighten anything that was previously "allow the whole tool." Move module-specific skills into nested directories. And if you run unattended agents, the pre-launch classifier change alone is worth the upgrade. This release connects straight to story one. The scaffold is the product, and Anthropic just gave you finer control over the scaffold.