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restart_zen

Restart Zen Browser with custom binary path, environment variables, headless mode, or preferences. Closes all tabs to apply new settings.

Instructions

Restart Zen with different configuration. Allows changing binary path, environment variables, and other options. All current tabs will be closed.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
envNoNew environment variables in KEY=VALUE format (optional, e.g., ["MOZ_LOG=HTMLMediaElement:5", "MOZ_LOG_FILE=/tmp/ff.log"])
prefsNoZen preferences to set at startup. Values are auto-typed: true/false become booleans, integers become numbers, everything else is a string. Requires MOZ_REMOTE_ALLOW_SYSTEM_ACCESS=1.
zenPathNoNew Zen binary path (optional, keeps current if not specified)
headlessNoRun in headless mode (optional, keeps current if not specified)
startUrlNoURL to navigate to after restart (optional, uses about:blank if not specified)
profilePathNoZen profile parent path (optional, keeps current if not specified)
Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries full burden. It discloses that all current tabs will close, which is a critical side effect. However, it does not mention potential data loss, required permissions, or whether the operation is reversible, limiting transparency for a restart action.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact with two sentences. The first sentence states the core action and purpose, and the second adds a key behavioral note. No redundant text is present, making it efficient for agent parsing.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the 6 parameters and no output schema, the description covers the main action and a key side effect but lacks details on process flow, error handling, or prerequisites (e.g., Zen must be running). It is adequate but leaves gaps for an agent needing full context.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all parameters. The description adds minimal extra meaning beyond stating configuration options, thus meeting the baseline for high coverage without exceeding it.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action (Restart) and resource (Zen), and specifies the purpose of changing configuration. It distinguishes from siblings like 'close_page' or 'navigate_page' by focusing on restart with configuration changes, and notes that tabs will close.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies the tool is for restarting Zen with new configuration but does not explicitly state when to use it vs. alternatives (e.g., 'navigate_page' for just navigation). No exclusion criteria or prerequisites are mentioned, leaving the agent to infer context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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