create_iphone_mockup

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

No annotations are provided, so the description must convey behavioral traits. It explains cover-fitting of screenshots, the effect of 'bleed' (phone bleeds off bottom), and using 'add_frame' to avoid phone-inside-phone. However, it does not mention whether the tool overwrites output, error handling, or file size limits. The disclosure is adequate but not exhaustive.

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 well-structured with a brief introductory sentence followed by a bullet-like Args list. It is concise (about 150 words) and front-loaded with the tool's purpose. Every sentence adds value. Minor inefficiency: the Args section could be more compact, but overall it's clear and readable.

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 the tool has 10 parameters (5 optional) and an output schema exists, the description is fairly complete. It covers parameter usage, includes a usage guideline for title drafting, and explains key behaviors. It does not discuss return format or error scenarios, but the output schema likely covers that. The description addresses the main purpose and common edge cases.

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 10 parameters with 0% description coverage, so the description must compensate. It does so excellently by describing each parameter in the Args section, including examples for 'size' (valid dimensions), explanation of 'bleed' and 'add_frame' behaviors, and details for 'bg_color' (hex, gradient with comma). This adds significant value 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 the tool wraps an app screenshot in an iPhone 16 Pro frame with marketing text to produce an App Store-ready preview. It distinguishes from siblings 'create_iphone_mockups_batch' (batch) and 'suggest_themes' (themes) by being a single-image mockup. However, it does not explicitly state when to use this vs the batch variant.

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 explicit guidance: if the user hasn't dictated the title, the agent should draft one (3-7 words, benefit-led) and get approval before calling. This is a clear usage guideline. It does not specify when not to use the tool or compare to alternatives, but the guidance is actionable.

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