zeph_file

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

The description adds behavioral context beyond the minimal annotations: images render inline, file types are enumerated, and the two modes are explained. It doesn't contain contradictions with the annotations (readOnlyHint=false, destructiveHint=false) and offers useful operational details such as the 'never base64' rule, though it doesn't cover error handling or permission requirements.

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 two sentences, front-loaded with the core action, and packs essential usage guidance without any waste. Every clause contributes meaning, making it an exemplar of concision.

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 description covers the main use cases and relies on the schema for parameter details. However, it omits the implicit requirement that at least one of filePath or content must be provided, and doesn't state what happens if neither is passed. Given the optional parameters, this leaves a small completeness gap.

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%, so the baseline is 3, but the description significantly enhances parameter understanding by linking filePath to existing files and content to generated text, and clarifying that filePath is required for images/PDFs/binary. The 'never base64 a file into content' warning adds crucial semantics not present in the schema.

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 primary function: 'Send a file to the user's device.' It distinguishes itself from siblings like zeph_notify or zeph_clipboard by focusing on file transfer, and further clarifies two distinct modes (filePath for existing files, content for generated text). This is a specific verb+resource with a 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?

The description provides clear guidance on when to use filePath vs content, including an explicit warning against base64-encoding binary files into content. It lacks an explicit comparison to sibling tools or a 'when not to use' clause, but the context is sufficient for an agent to select it for file-sending tasks.

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