View an image attachment

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

Annotations already indicate read-only and open-world behavior, but the description adds key behavioral context: the tool returns a viewable image and is the only way to see photos/scans under certain conditions. This goes beyond the annotations without contradiction.

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, front-loaded with purpose, then return format, then constraint and alternative. Every sentence adds value with no fluff or repetition.

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 annotations and schema, the description covers purpose and return type but omits parameter roles and any error/output behavior. The absence of an output schema and partial parameter descriptions leaves gaps, but the tool is simple and the core usage is clear.

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 50%, but the description provides no additional parameter guidance. It does not explain the role of uid, folder, or uidvalidity, nor how 'filename' partial matching works. The description says 'image attachment' but not how to identify it, leaving the agent to rely on sparse schema hints.

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 the tool's purpose: 'Look at an image attachment' and 'Returns it as a viewable image'. It explicitly distinguishes from read_attachment for text and PDFs, and the title adds image-specific context. This is a specific verb+resource with clear scope.

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?

Directly says 'Images only, use read_attachment for text and PDFs,' naming the alternative tool and the condition for selection. Also mentions the scenario 'when the client cannot read local files,' providing clear when-to-use guidance.

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