图片格式转换（png/jpeg/webp 互转），产物落文件中转站返下载 URL（1 credit/次）。
| Name | Required | Description | Default |
|---|---|---|---|
| to | Yes | 目标格式 png / jpeg / webp | |
| file_id | No | 图片文件 ID（与 data_base64 二选一） | |
| quality | No | jpeg/webp 质量 1-100；缺省用推荐值 | |
| filename | No | 输出文件名（可选） | |
| data_base64 | No | 图片内容 base64 |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description adds useful behavioral context: the output is stored in a file transfer station and a download URL is returned, and each call costs 1 credit. This is beyond what the schema provides, though it does not disclose all side effects.
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 a single sentence that is front-loaded with the core purpose and includes essential behavioral details. There is no redundant information.
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 no output schema and no annotations, the description effectively communicates the output behavior (download URL) and cost. It is complete enough for a relatively simple tool, especially with schema covering parameter constraints.
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 schema descriptions cover all parameters (100% coverage), so the baseline is 3. The description does not add parameter-specific details beyond what the schema already states, except clarifying the credit cost which is not parameter-related.
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 performs image format conversion among png/jpeg/webp. It is distinct from sibling tools like img_compress or img_resize, as it specifically targets format conversion.
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 implies the tool should be used when format conversion is needed, but it does not explicitly mention alternatives or when-not-to-use. The context is clear but relies on inference from the purpose.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Most tools are clearly distinct, but img_compress and img_convert both support format changes, and img_info and img_exif both read metadata, creating minor overlap. The descriptions help clarify the primary purposes, so ambiguity is low.
All tools share the img_ prefix and mostly use verb-based names like img_compress and img_resize. However, img_info and img_exif are noun-based, which is a slight deviation from the pattern, though still predictable and readable.
With 8 tools, the server is well-scoped for an image toolbox. Each tool addresses a common operation without unnecessary additions, making the count appropriate for the stated purpose.
The toolset covers the core image lifecycle: inspecting info, reading EXIF, compressing, converting, resizing, cropping, rotating, and watermarking. There are no glaring gaps for a practical image toolbox, so agents can handle typical workflows end-to-end.