edit_image_pixen

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full behavioral burden. It takes on that burden by disclosing that only the requested changes occur, that the model re-renders at the target size rather than rescaling, and that the operation costs 1 generation. It stops short of a 5 because it does not state whether the original image is overwritten or what the return payload looks like.

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 dense but every sentence earns its place: core promise, source constraint, target semantics, re-render behavior, cost, and the sibling-tool routing. It is front-loaded with the core purpose and contains no filler.

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 the absence of an output schema and annotations, the description covers the most important operational facts: model, source size, target size rules, cost, and when to prefer it. The remaining gap is the lack of explicit return-value or side-effect semantics, but the parameter schema fills in most technical details.

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 already documents all six parameters, but the description adds meaning beyond the field descriptions: it specifies the maximum source size, explains that target dimensions default to source dimensions, gives the valid canvas area range, and clarifies the re-render vs rescale behavior. This genuinely helps an agent pick correct width/height values.

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: 'Edit an existing pixel art image with a text instruction on the Pixen model.' It further differentiates the scope by explaining what is preserved ('pose, composition and pixel style') and distinguishes it from the generic edit_image sibling.

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 clear context for when to use this tool ('Prefer this over edit_image for Pixen-generated art') and includes practical constraints like the 256px source limit and target canvas area. It does not explicitly exclude other edit variants such as edit_image_pro_flash or inpaint, so it falls just short of fully exhaustive usage guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.