Resize an image to fit within specified width and height limits while preserving its original aspect ratio, using a local file path to output an adjusted version.
Scale an image to fit within width x height (aspect ratio preserved).
| Name | Required | Description | Default |
|---|---|---|---|
| width | Yes | Max width in pixels | |
| height | Yes | Max height in pixels | |
| image_path | Yes | Local path to the image |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure. It states only the scaling behavior and aspect-ratio preservation, but omits whether the original file is overwritten, where or how the resized image is returned, and what happens with unsupported formats—critical side effects for a tool with no output schema.
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?
A single 11-word sentence with no filler; the core constraint ('fit within width x height') and behavior ('aspect ratio preserved') are front-loaded. Every word contributes, and there is no unnecessary structural complexity.
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 simple three-parameter tool, the description should still clarify the output/return behavior, especially because there is no output path parameter or output schema. The description doesn't state whether the image is modified in place, where the result is written, or what the tool returns, leaving a significant gap for an agent trying to use the result.
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%, so the schema already documents all parameter meanings ('Max width in pixels', 'Max height in pixels', 'Local path to the image'). The description adds the 'fit within' framing and aspect-ratio preservation, but no additional syntax or format details, matching the baseline 3 for high schema coverage.
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 uses a specific verb ('Scale') and identifies the resource ('an image'), with precise constraints ('to fit within width x height', 'aspect ratio preserved'). It clearly states the tool's function, though it doesn't explicitly contrast with related siblings like upscale_image or image_thumbnail, so it's clear but not sibling-differentiated.
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 gives no information about when to use resize_image instead of alternatives such as upscale_image or image_thumbnail, nor any exclusions. An agent must infer the appropriate choice from the tool name and sibling list, so there is effectively no usage guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.