get_image_bitmap

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

No annotations exist, so the description carries the full burden, and it does well: it discloses the return format (PNG, base64, MIME type per MCP spec), states there are no size restrictions, and enumerates failure conditions ('RuntimeError if no image is open, region is invalid, or export fails'). It stops short of stating performance/resource implications of full-resolution export on very large images, which an agent planning calls would benefit from.

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?

Well front-loaded with the core action first, then use cases, parameters, examples, returns, and raises. The examples and returns sections earn their place given the absent output schema, though the two closing sentences about automatic base64/MIME handling restate the same point twice.

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 3-parameter, zero-annotation, no-output-schema tool with 0% schema description coverage, the description supplies everything needed: object shape, nested region keys, scaling semantics, concrete call examples, return payload contents, and error conditions.

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 0%, and the description fully compensates: it defines max_width/max_height as target dimensions with aspect ratio preserved, and unpacks the untyped region dict into origin_x, origin_y, width, height plus optional nested max_width/max_height. This is meaning the schema literally cannot convey, since region is only an open object type.

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+resource ('Get the current open image in GIMP as an Image object') plus the two capabilities (scaling, region selection). It is clearly distinguishable from siblings like get_image_metadata (metadata only) and export_image (writes to disk) without opening any schema.

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?

Gives explicit usage scenarios ('Full image with optional scaling' vs 'Region extraction') and a sizing hint ('For large images, omit max_width/max_height'). It does not explicitly say when to prefer this over siblings such as get_image_metadata, export_image, or get_pixel_color, so routing guidance is implied rather than stated.

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