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

Beyond the non-destructive and non-idempotent annotations, the description explains important behavior: data URLs are normalized and uploaded to AIGE Storage, gallery entries become fetchable HTTPS URLs, and the latest image is automatically used by antix_generate_image when no explicit referenceImage is provided. It also notes visibility in the AIGE web PromptBar and describes rejected URLs in the return value.

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, organized into Inputs, workflow, and Returns sections, and each section is useful. It is somewhat verbose and repeats the 'latest gallery image as the img2img reference' point in both the opening and the workflow steps, but this repetition is minor and does not obscure the core guidance.

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 fully described for a two-parameter append operation with no output schema. The description covers input formats, fallback behavior, side effects, the downstream auto-img2img behavior, and the return fields including rejected URLs and totalImages. An agent has enough information to call it correctly without further clarification.

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%, so the description carries the full burden. It explains that characterId comes from antix_list_characters, that images accepts HTTPS URLs or base64 data URLs, and that 1-20 images are allowed per call, matching and enriching the schema constraints.

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 opens with a specific verb and resource: 'Append images to a character's saved reference gallery.' It clearly distinguishes the operation from sibling tools such as antix_list_character_gallery and antix_generate_image by explaining that this tool populates the gallery and that antix_generate_image later consumes the latest entry.

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?

It provides explicit when-to-use guidance, including a four-step workflow for bridging chat-attached images into the img2img flow. It also states the fallback behavior when the Claude client cannot forward image bytes, directing the user to https://aige.ws/r and then calling the tool with the resulting URL.

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