获取图片元信息

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

Annotations already mark it read-only, idempotent, and non-destructive. The description adds that it returns a defined set of metadata fields and accepts either a local path or URL. This is useful additional behavioral context beyond the annotations.

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 short and front-loaded, with the metadata payload listed clearly. The separate '参数' bullet is slightly redundant with the input schema but not bloated.

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 one-parameter, read-only metadata getter with annotations and an output schema, nothing essential is missing. The description covers purpose, accepted input format, and the returned metadata categories.

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%: the sole parameter's description already explains the URL-vs-local-path distinction. The tool description repeats '图片路径或URL' but adds no new meaning, so the baseline 3 for full schema coverage is appropriate.

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 action — get image metadata — and enumerates exact returned fields (width, height, format, channels, color space, DPI, alpha channel, EXIF orientation). This clearly separates it from sibling vision/image-manipulation 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?

It establishes clear context: use when you need image metadata such as dimensions, format, or EXIF orientation. It does not explicitly name alternatives or exclusion conditions, so it misses the top score, but the context is specific enough for routing.

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