Gallery Page

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

Annotations already indicate read-only and non-destructive behavior, so the description adds value by explaining the helper/pagination nature and the direct-invocation caveat. It does not contradict annotations or the schema, and the read-only hint is consistent with 'Return a page'.

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 two sentences, front-loaded with a clear action, and every sentence earns its place. It avoids marketing fluff, tautology, or repetition of the title/schema, making it highly concise and well-structured.

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 tool is simple (3 optional params, read-only), and the description, combined with a rich schema and output schema, fully explains its purpose, usage boundary, and pagination behavior. It tells the agent exactly when to use it (by the UI) and when not to (direct model invocation), leaving no significant gaps.

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 covers 100% of parameters with detailed descriptions (page, origin, page_size), so the description doesn't need to add parameter-level meaning. It provides only a high-level 'page of thumbnails' context, which is not parameter-specific. Schema carries the semantic load, meriting baseline 3.

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 a specific action ('Return a page of image thumbnails') and resource ('gallery UI'), immediately distinguishing itself from sibling tools like show_image or gallery_full_image. It also adds scope ('pagination') which reinforces its unique role among gallery 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 explicitly says this is an 'App-only helper called by the gallery UI' and 'Not intended for direct model invocation,' giving clear when-to-use and when-not-to-use guidance. It doesn't explicitly name alternatives, but the exclusion is strong and contextually sufficient given sibling names.

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