draw_image

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

The description goes beyond the annotations by defining each mode's effect: 'blend' composites, 'copy' overwrites the area, 'replace' swaps the whole cel image. That is real behavioral disclosure for a mutating tool whose annotations only say readOnly=false/destructive=false. It does not mention undo/reversibility or that batch mode writes to disk, which would complete the picture.

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 tight sentences, front-loaded with the core action and destination, then mode semantics, then the optional transforms. Every clause adds information with 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?

For a 15-parameter mutation tool with no output schema and minimal annotations, the description covers the destination and modes but omits return/error behavior, undo implications, and the live-vs-batch save semantics. It is enough to attempt a basic call but not enough to use the tool confidently across backends.

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 low (33%), so the description must carry weight, and it does explain mode semantics plus the existence of source crop, scale and target size. However, it says nothing about x/y placement origin, opacity, blendMode, frame/layer/sprite resolution, or the save/batch distinction, leaving many of the 15 parameters undocumented in both places.

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?

States a specific verb and resource ('Draws an image file (PNG, etc.) into a layer/frame at (x,y)'), which implicitly separates it from draw_pixels, draw_shapes and draw_text by input type. No sibling is named explicitly, so an agent must infer the boundary rather than being told it.

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?

Usage is only implied: you use it when you have an image file to place. There is no explicit 'use this instead of draw_pixels/draw_shapes when...' guidance, and no note about when live vs batch backend is required (only the schema covers backend/save).

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