Gemini CLI: Plan Mode Matures with MCP Integration and Tool Output Masking
Gemini CLIGemini CLI v0.29.0 marks a significant maturation of Plan Mode, now extended to support MCP servers for read-only research queries during the planning phase. The release also introduces tool output masking by default, which intelligently compresses large tool responses to conserve context tokens. Additional improvements include a new /plan slash command, an MCP allowlist for administrators, and autocomplete in the input prompt.
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Plan Mode Reaches a New Level of Capability
With v0.29.0, released February 18, 2026, Gemini CLI's Plan Mode graduates from an early experimental feature into a more fully realized agentic workflow tool. The headline advancement is MCP server support within Plan Mode: Gemini CLI can now invoke read-only MCP tools — such as querying a GitHub issue, reading a Postgres schema, or fetching API documentation — during the research and design phase of a plan, before any code-writing tools are made available.
A dedicated /plan slash command now provides direct entry into Plan Mode from the interactive session. Once activated, write operations are constrained to Markdown files within the designated plans directory, ensuring that the planning phase remains non-destructive.
Tool Output Masking: Smarter Context Management
One of the most practically impactful changes in v0.29.0 is the enablement of tool output masking by default. When an agent executes many tools in a long session, the accumulated outputs from earlier tool calls consume an increasing share of the context window. Tool output masking addresses this by compressing older tool outputs that are no longer high-signal, automatically substituting them with compact summaries while preserving the most recent and most important results.
This change has measurable implications for developers working on long-running tasks: sessions can now run substantially longer before hitting context limits, and token costs are reduced accordingly.
Security and Administrative Controls
The v0.29.0 release adds an MCP allowlist mechanism that gives enterprise administrators control over which MCP servers agents are permitted to connect to. Folder trust handling has also been hardened with atomic writes and additional safety checks. SSL/TLS error handling now includes retry logic, and .env file loading is restricted in untrusted sandboxed folders.
Developer Experience and UX Improvements
Autocomplete is now available in the input prompt, making command discovery faster. A shortcuts hint panel surfaces available keyboard bindings for new users. Thinking bubbles now support both summary and full display modes. For developers building on Gemini CLI, v0.29.0 adds WebSocket-based network logging, DevTools access via F12, and model-specific tool definitions.