View an image

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

No annotations are supplied, so the description has to carry the full disclosure burden, and it delivers meaningful context: the tool returns a viewable image rather than text, the accepted formats (PNG, JPEG, GIF, WebP), and a hard 4.8 MB limit that can cause failure. It stops short of failure-mode behavior (what happens if the file is too large or missing) and says nothing about whether URL or remote paths are accepted.

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 short sentences, front-loaded with purpose, then formats and constraint, then the alternative. Almost nothing is wasted, though the parenthetical examples sit slightly awkwardly in the opening sentence rather than in a dedicated clause.

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 one-parameter read tool with no output schema, the definition covers purpose, accepted formats, size ceiling, and the nearest alternative, which is nearly everything needed to invoke it correctly. The only real gap is path-form expectations, which neither the description nor the schema addresses.

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?

There is only one parameter and schema coverage is 100%, with the schema itself describing it as 'Image file path.' The description adds no further meaning about path semantics, such as whether relative, absolute, or URL-style paths are valid. With the schema doing the work, a baseline 3 is appropriate.

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 names a specific verb and resource ('Returns an image file so you can actually see it') and grounds it with concrete examples (screenshots, design mockups, diagrams). It also explicitly separates itself from the sibling read_file, which handles text, so an agent can pick correctly without opening either 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?

The routing rule is explicit and unambiguous: use this for images, and 'For text files use read_file.' It even matches the formats and size ceiling to the use case, so the agent knows exactly when this tool applies versus the closest alternative.

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