Fetch a PNG image and metadata for a specified Aseprite document revision and frame, enabling previews of unsaved canvases with optional integer nearest-neighbor scaling and region cropping.
直接返回指定修订/帧的 PNG 图片及元数据；整数最近邻缩放。
| Name | Required | Description | Default |
|---|---|---|---|
| frame | No | ||
| scale | No | ||
| region | No | ||
| session_id | Yes | ||
| document_id | Yes | ||
| expected_revision | Yes |
Changes observed during successful MCP inspections.
v0.5.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It discloses the return format (PNG image plus metadata) and nearest-neighbor scaling, but omits read-only/side-effect safety, permission requirements, revision-mismatch behavior, and session/document constraints.
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 one compact sentence with no filler and front-loads the return action. The trailing scaling detail is useful but makes the sentence slightly terse rather than fully 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?
There are no annotations, no output schema, and six parameters with zero schema descriptions. The description gives the core purpose and output format, but it is not complete enough for correct invocation of a multi-parameter read tool.
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% for all six parameters. The description only partially covers revision, frame, and scaling concepts, while session_id, document_id, and region are left undocumented.
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 verb and resource: it returns a PNG image and metadata for a specified revision/frame. This is distinguishable from siblings such as list_documents or get_document_info, though it does not explicitly name alternatives.
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 only says the tool directly returns a preview image for a revision/frame; there is no explicit when-to-use, when-not-to-use, or alternative selection guidance among sibling tools. The agent must infer the usage context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.