google-gemini/gemini-cli

Command substitution block should be user-configurable, not a hardcoded wall

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#27393 opened on May 23, 2026

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 (9 comments) (0 reactions) (1 assignee)TypeScript (103,992 stars) (13,657 forks)batch import
area/agenthelp wantedkind/enhancementpriority/p3status/bot-triagedstatus/possible-duplicate

Description

What would you like to be added?

A allowCommandSubstitution toggle in settings.json (defaulting to false) that lets users opt out of the hardcoded command substitution block. In YOLO mode, this should either default to true or surface a warning instead of a silent block so the model can adapt its approach.

Why is this needed?

The current hardcoded block creates two problems:

  1. Token/turn waste — the model writes out a full command with $() substitution, the CLI blocks it at execution time, and the entire turn is wasted with nothing to show for it. The model has no way to know in advance the command will be blocked.

  2. YOLO mode contradiction — in YOLO mode the user has explicitly opted into "run everything without asking me." Silently blocking an entire command class undercuts that contract without any warning.

A configurable toggle keeps the safe default for everyone while letting users who understand the risk opt out.

Additional context

Reproduction: run any agentic task that requires command substitution (e.g. security triage, process inspection) in YOLO mode. The model generates a valid command, the CLI blocks it silently, the turn is lost, and the tokens still count against the user's quota — making this a compounding cost with no output to show for it.

Contributor guide

Tech stack
typescriptnodejs
Domain
cli
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
blocked
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Understanding of CLI settings configurationBasic knowledge of command execution in Node.js
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Examine the repository's settings configuration (likely in settings.json or a configuration module) and the command execution logic that currently blocks command substitution. Look for where the 'block' is enforced and where settings are read. The issue suggests adding an 'allowCommandSubstitution' toggle defaulting to false. Consider implementing the toggle and integrating it into the existing settings validation and command execution pipeline. Check if there is a YOLO mode setting that could override or interact with this toggle.