view_image

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

Annotations only declare readOnlyHint=true, so the useful additions here are the output characteristics: a JPEG capped at 1568 px on the long edge, which tells the agent the resolution and payload cost before calling. It leaves open what happens for unsupported formats or missing/remote files, but that is a modest gap given the annotation covers safety.

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 sentences, zero filler: the capability and accepted input types come first, then the concrete return format. Nothing in it is redundant or buried.

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?

With an output schema and full schema coverage present, the description supplies the right residual information: what inputs are renderable and what the returned artifact looks like. The main missing piece is failure behavior for unsupported formats or unusable paths.

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 100%, with both path and node_id already documented in the schema, so the description does not need to restate them. It adds no guidance on which identifier to prefer or how the two interact, so it tracks the baseline rather than exceeding it.

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 opens with a specific verb+resource ("Look at a file as an image") and enumerates the accepted inputs (image formats, video cover frame, PDF/Office first page), so an agent knows exactly what it gets back. It separates itself implicitly from text siblings like read_text_file/read_document_text via the image return, but never names those alternatives outright.

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: the supported-format list hints that this is the tool to pick for visual inspection of media and document pages rather than text extraction. There is no explicit when-to-use, when-not-to-use, or named alternative for the read_text_file/read_document_text case.

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