update_image

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

With no annotations, the description must fully explain behavior. It mentions in-place replacement and preservation of dimensions/position, but does not disclose side effects (e.g., overwriting, undo, permissions, file validation) or whether the document needs to be saved. This is insufficient for a mutation tool.

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 concise (3 sentences) with a clear first sentence stating the action, followed by a preservation guarantee and an Args list. No redundant information, and the essential purpose is front-loaded.

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 there is an output schema, the description needn't explain return values. However, it omits important context like image format compatibility, that the path must exist, or that the document must be open. Considering the simple operation, it is minimally complete but could be more helpful.

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?

Both parameters (rId, new_image_path) are described clearly beyond the input schema, which only defines types. The description adds meaningful context: rId is the relationship ID, new_image_path is an absolute path. Schema coverage is 0%, so the description compensates well.

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 it replaces the binary of an existing image while preserving dimensions and position. This distinguishes it from related tools like insert_image (adds new image) and set_image_size (changes dimensions).

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 does not explicitly state when to use this tool versus alternatives such as insert_image or set_image_size. It implies usage for replacing image content while keeping layout, but lacks guidance on when not to use it or prerequisites.

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