Convert images between png, jpeg, webp, avif, and bmp by setting input and output paths; the output extension must match the chosen format.
Convert an image to png, jpeg, webp, avif or bmp. The output extension must match.
| Name | Required | Description | Default |
|---|---|---|---|
| format | Yes | ||
| overwrite | No | ||
| input_path | Yes | ||
| output_path | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| width | Yes | ||
| format | Yes | ||
| height | Yes | ||
| output_path | Yes | ||
| input_format | Yes | ||
| output_bytes | Yes |
Changes observed during successful MCP inspections.
v0.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true, idempotency=false and readOnlyHint=false, so the safety profile is covered. The description adds one genuinely useful behavioral rule — that the output extension must correspond to the requested format, which is a validation failure mode. It says nothing about what overwrite destroys, however, which is the main destructive behavior.
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?
Two short sentences, verb and resource front-loaded, no filler. Nothing in the text could be removed without losing 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?
An output schema exists, so return values need not be described, and the destructive/overwrite risk is partly implied by annotations. Still, for a 4-parameter mutation tool with 0% schema coverage and a file-overwriting behavior, omitting any explanation of overwrite or path handling leaves a real gap.
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 carry the parameter burden and does not. It implies format values (png/jpeg/webp/avif/bmp) but never explains input_path, output_path, or the semantics of the overwrite flag, which is the most consequential parameter given destructiveHint=true.
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?
Names a specific verb (Convert) and resource (an image) and enumerates the five target formats, so an agent knows exactly what the tool does and can tell it apart from image_resize/image_optimize. It stops short of explicitly contrasting itself with those siblings, which keeps it at 4 rather than 5.
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 only guidance is a constraint ("The output extension must match"), not a when-to-use rule. Nothing says when to pick image_convert over image_optimize or image_resize, nor when the optional overwrite should be enabled.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.