insert_image

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

With no annotations, the description carries the transparency burden. It discloses that the tool mutates the workbook, depends on Pillow, supports PNG/JPG/GIF, and returns metadata. However, it omits details like how sizing works, whether images are replaced, and error behavior. The note "Document supported image formats and sizing behaviour" is a placeholder, not actual behavioral documentation.

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 organized with sections for Args, Returns, and Notes, making it scannable. The main purpose is front-loaded. The Notes section includes a meta-instruction to "Document supported image formats and sizing behaviour," which is not useful to the agent and could be considered filler, but overall the length is appropriate.

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?

The tool has 6 parameters, no annotations, and no output schema, so the description is the sole reference. It covers the basic use case, parameter meanings, return type, and a side effect (mutation). However, it lacks details on image resizing, how the anchor cell is interpreted, and failure modes, leaving gaps that the placeholder note explicitly acknowledges.

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%, so the description must compensate. The Args section explains each parameter, adding value such as "Optional width in Excel units" and "Path to image (PNG/JPG/GIF)." This goes beyond the raw schema, clarifying optional status and units, though it does not fully elaborate on all edge cases.

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 begins with a clear, specific statement: "Insert an image into a worksheet anchored at a target cell." This identifies the action (insert), the resource (worksheet image), and the key detail (anchored at a cell), which distinguishes it from siblings like chart or comment.

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 implies when to use the tool (when inserting an image) but does not explicitly contrast it with alternatives such as chart, hyperlink, or comment. It lacks exclusions or specific scenarios, yet the purpose is clear enough for an agent to infer basic usage.

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