describe_image

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

No annotations are present, so the description carries the burden. It discloses supported image sources (local paths, URLs, file://, data URIs) and states that it returns a text description. It does not mention potential limitations or side effects, but for a simple read-only vision tool, this is mostly sufficient. A note about accuracy or model behavior could push it higher.

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 into purpose, usage cases, args, and returns. It is front-loaded with the core purpose, and every sentence adds value. The formatting uses clear paragraph breaks and a simple Args list, making it easy to scan.

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's simplicity (2 parameters, no annotations, output schema present), the description covers all necessary aspects: what it does, when to use it, parameter semantics, and return value. It is complete and self-contained.

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 description includes an Args section that explains image formats (本地路径, http(s)://, file://, data:image/...;base64,...) and prompt guidance ('越具体越好；留空返回通用描述'), adding significant value beyond the schema, which has zero descriptions for either parameter.

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 '识别单张图片并返回文字描述' – a specific verb (识别) + resource (单张图片) + output (文字描述). It clearly distinguishes from siblings by emphasizing '单张' and '任意图片' coverage, making it unambiguous when this tool should be selected.

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 explicitly states when to use: '当用户让你"看/读/识别"一张图片...' and provides an exclusion: '请勿用文件读取工具直接读图片'. However, it does not name sibling alternatives like extract_text_from_image or analyze_images, so the distinction from those tools is implied rather than explicit.

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