init_viewer

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

No annotations are provided, so the description must fully disclose behavioral traits. It clarifies that detect_only=True reports viewers without initializing, and mentions port for external bridge. However, it does not describe what 'return' means (return value) or any side effects like viewer display state.

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 front-loaded with the main purpose and includes a well-organized parameter section. However, the parameter documentation is somewhat verbose; each parameter's explanation could be more concise.

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?

Given 5 parameters and no annotations, the description covers parameters comprehensively. However, it omits explanation of the return value despite an output schema existing, leaving a gap in completeness.

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?

Schema description coverage is 0%, but the description includes detailed parameter documentation (title, width, height, port, detect_only) explaining their purpose and defaults. This adds significant meaning beyond the bare schema.

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 'Create or return the napari viewer, with viewer detection.' It uses specific verbs and a distinct resource, differentiating from siblings like close_viewer or configure_viewer.

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 explains the detect_only mode and its use case, providing context on when to use this tool without creating a viewer. However, it does not explicitly contrast with sibling tools like close_viewer or configure_viewer.

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