preview_html

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

With no annotations provided, the description carries the full disclosure burden. It clearly reveals the preview/print behavioral trait (returns exact printed output, no physical printing), explains rendering details (1-bit, dithering), and discloses capabilities like QR generation and remote image support. This is rich behavioral context.

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 somewhat long but every sentence earns its place: it describes output fidelity, canvas dimensions, style support, special features, and usage guidance. The key differentiator ('Render... WITHOUT printing') is front-loaded.

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?

For a 3-param tool with no output schema and no annotations, the description is thorough. It covers canvas specs, supported features, QR generation, mode selection, and ties to design_guide and print_html. Minor gap: no mention of return value format (image data vs URL), but overall it's quite complete for the tool's complexity.

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 coverage is 100%, so the schema documents all three parameters. The description adds meaningful value by explaining the html canvas spec (58mm, 384px wide, unlimited height), the QR data attribute feature, and clarifying mode/algorithm semantics (auto detects photos vs text, bayer gives halftone look). This goes beyond the 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 states a specific verb+resource ('Render ticket HTML WITHOUT printing') and clearly distinguishes from the sibling print_html by emphasizing the preview-only behavior. It also explicitly notes it returns the exact 1-bit printed image, making its functional scope unmistakable.

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 gives explicit guidance: 'always preview before print_html', directly telling the agent when to use this tool relative to its sibling. It also instructs calling design_guide first or reading the thermal-print skill, adding clear context for proper usage.

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