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

With no annotations, the description carries the full behavioral burden. It discloses auto-backup behavior, backup slot locations, an atomic validated save, and the Word-open refusal. The phrase 'skips rotation only' is ambiguous, but the overall side-effect and safety picture is unusually clear for a short description.

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?

Three dense sentences deliver the primary function, prerequisites, side effects, and a failure condition without waste. Every clause adds useful operational 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?

Given the tool modifies an image in a document, the description covers what the tool does, how to identify the image, backup behavior, save behavior, and a hard failure condition. The 'prev/anchor slots' and 'skips rotation only' phrasing is slightly jargony, and file_path semantics are only implied, but an agent has enough to invoke it correctly.

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 compensate for all four parameters. It clarifies width_pt as the target width, image_index as coming from list_images, and backup's effect on backup rotation. file_path is not explicitly named but is implied by 'documents open in Word.'

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: 'Resize an inline image to width_pt, aspect ratio kept.' It also identifies how the target image is selected ('image_index from list_images'), which clearly distinguishes this from related image tools like replace_image or set_image_alt_text.

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 explicit usage context by directing the agent to obtain image_index from list_images and by noting that documents open in Word are refused. It does not name alternative tools or explicitly say when to use an alternative, so it stops short of full routing guidance.

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