Compare two versions of a photo edit to quantify visual differences with ΔE, SSIM, PSNR, and colour-distribution metrics, plus a side-by-side image for review.
Metrics (ΔE, SSIM, PSNR, colour-distribution distance) between two versions + side-by-side image.
| Name | Required | Description | Default |
|---|---|---|---|
| a | No | original | |
| b | No | current | |
| project_id | Yes | ||
| include_image | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the operation as read-only, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds useful return-content context by naming the metrics and side-by-side image, but does not disclose defaults, error behavior, or how versions are resolved.
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 compact sentence with the key metrics front-loaded and no wasted words. Its brevity is effective as a summary, even though other dimensions need more detail.
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?
With four parameters, zero schema descriptions, and no output schema, the description should carry more of the invocation burden. It partially describes the return content, but leaves parameter meaning, defaults, and usage conditions unclear, so an agent cannot confidently invoke it without inspecting the schema.
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%, so the description must explain the four parameters, but it does not. It hints at comparing two versions and optionally including an image, yet never explains a, b, project_id, include_image, or their defaults, leaving the required project_id especially 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 clearly states that the tool computes comparison metrics between two versions and produces a side-by-side image, naming specific metrics. It is specific about the resource and output, but does not distinguish this tool from nearby alternatives such as inspect_image or render_preview.
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 explicit guidance on when to use this tool versus alternatives, nor any conditions or exclusions. At best, usage is implied by the mention of comparing two versions.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.