navvi_start

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

No annotations are provided, so the description carries the full burden. It discloses that 'All input is OS-level (isTrusted:true)' and provides a CAPTCHA handling strategy. It does not elaborate on container lifecycle or persistence, but the workflow and behavioral notes are fairly comprehensive.

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

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

The description is moderately concise and well-structured: it starts with the primary purpose, then environment, then a workflow, then a note on CAPTCHA. While it could be slightly trimmed, each sentence adds value and the flow is logical.

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

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

The description covers workflow, environment, and a special case (CAPTCHA). However, it does not explain output semantics (despite an output schema likely existing) and leaves parameters undocumented. For a start tool, it provides adequate but not complete context.

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

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

The input schema has three parameters (persona, mode, name) with defaults, but the description provides no explanation of their meaning or usage. Schema description coverage is 0%, and the description fails to compensate, leaving the agent without guidance on how to use these parameters.

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

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

The description clearly states 'Start a Navvi browser container' and specifies the components (Firefox + Xvfb + xdotool). It differentiates between local and remote environments. However, it does not explicitly contrast with sibling tools, though 'start' is intuitively the initializer among many interaction tools.

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

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

The description provides an explicit workflow: 'navvi_open(url) -> navvi_find(selector) -> navvi_click/navvi_fill -> navvi_screenshot to verify.' It also offers a fallback for CAPTCHA by calling navvi_vnc. This clearly indicates when to use this tool (at the start) and when to use an alternative.

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