Claude Code .claudeignore: stop leaking secrets and node_modules into your context
anthropic claude
| Source: Dev.to | Original article
Anthropic has rolled out a new .claudeignore feature for Claude Code, letting developers explicitly exclude files and directories from the model’s context. The change, announced on the project’s GitHub issue tracker, makes node_modules ignored by default and adds support for custom patterns—mirroring the behaviour of .gitignore. Until now Claude Code would automatically scan every file in a repository, pulling in massive dependency trees and, more worryingly, secret files such as .env or API keys. Those reads were sent to Anthropic’s servers, exposing credentials and inflating token usage.
The addition matters on three fronts. First, it plugs a glaring security hole: developers can now guarantee that sensitive configuration files never leave their machines, addressing concerns raised on Reddit in June 2025 and in a recent security blog post that showed the model leaking secrets during test runs. Second, it curtails token waste. Early benchmarks shared by the community suggest up to an 80 % reduction in token consumption for typical JavaScript projects, translating into lower costs for teams that bill AI usage by the token. Third, it aligns Claude Code with established developer workflows, making the tool feel less intrusive and more controllable within CI pipelines.
As we reported on 3 April 2026, Claude Code’s “model” field and recent bug‑workarounds have already sparked a wave of experimentation among Nordic AI developers. The next steps to watch are Anthropic’s rollout plan for the ignore file in its VS Code extension and the response from enterprise users who must comply with strict data‑handling policies. If the community adopts .claudeignore widely, we may see similar privacy controls appear in competing code assistants, potentially reshaping how AI‑driven development tools interact with source code.
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