Parallel sessions and git worktrees: run several Claude Code agents without collisions

One repo, several Claudes, zero stepped-on edits. Learn to give each Claude Code session its own git worktree, an isolated working directory on its own branch, plus the port, dependency, and database collisions to dodge, and the rule for when fanning out actually beats one focused session. Episode page & show notes Try a walking desk - stay healthy & sharp while you learn & code The first rung of Act two: stop driving one Claude Code session by hand and start running several in parallel without them colliding. The mechanism is git worktrees, multiple working directories backed by one repository, each on its own branch. The tutorial. What a git worktree actually is (shared history and object store, but isolated working files, HEAD, and index) and the one rule underneath everything: a branch can only be checked out in one worktree at a time, so each parallel session needs its own branch. The small command surface (git worktree add, list, remove, prune) and the nesting trap that pollutes your main checkout. Then Claude Code's built-in worktree support: the --worktree/-w flag, where it puts worktrees and how it names branches, basing each off origin/HEAD, the worktree.baseRef setting, branching straight off a PR number, the workspace-trust gotcha, the .worktreeinclude file for carrying your gitignored .env across, and isolation: worktree for the subagents we built back in Act one. The three collisions you'll actually hit, dependencies, ports (and why PORT in .env.local is silently ignored by the Next.js dev server), and the database, plus integration by pull request and partitioning work by file ownership. Finally, when NOT to fan out: the review bottleneck (roughly four to eight worktrees per developer before you're the constraint), coordination overhead, and the per-session token cost, drawing on Anthropic's best practices and cost guidance. News. Claude Code 2.1.160 and 2.1.161 (June 2): parallel tool calls are now fault-isolated, the Dynamic Workflows trigger keyword changed from "workflow" to "ultracode," and claude mcp stops printing your secrets, per the changelog. And the June 15 billing change: programmatic usage (the Agent SDK, claude -p, Claude Code GitHub Actions) moves to a separate metered credit pool billed at API rates, while interactive Claude Code stays unaffected, via The New Stack. Earlier episodes referenced: subagents, skills, CLAUDE.md, context windows, and cost and rate-limit engineering.