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

With no annotations, the description carries the disclosure burden. It explicitly states two behavioral traits: 'creating parent directories as needed' and 'Overwrites an existing file at that path.' This is useful transparency for a write operation. It does not discuss permissions, failure modes, or atomicity, but the core side effects (overwrite, directory creation) are disclosed.

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 sentences, each carrying meaningful information. The first sentence is action-oriented, the second provides usage context and a sibling reference, and the third states the overwrite behavior. No wasted words or redundancy with the schema.

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 file push tool with no output schema, the description is fairly complete: it defines the action, input format, key behaviors (parent dirs, overwrite), and the bundleId vs. shared media distinction. It lacks details about success/failure responses and edge cases like invalid paths, but those are not critical for basic operation. Sibling tools provide further context, but the description alone is sufficient for an agent to invoke it correctly in common scenarios.

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. The description adds extra meaning beyond the schema, particularly for bundleId: 'Same bundleId root selection as ios_file_list — pass it to seed an app's own container.' This clarifies the purpose of an otherwise abstract parameter and links it to a sibling tool's behavior, exceeding the baseline.

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 and resource: 'Write a file onto an iOS device from base64 content,' clearly distinguishing it from sibling file operations like ios_file_list (listing) and ios_file_pull (reading). It also clarifies key behaviors like parent directory creation and overwriting, making the tool's purpose unambiguous.

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?

It explicitly states the intended use case: 'seed an app's own container with fixture data, a config file or a test database before launching it.' It also references ios_file_list for the same bundleId root selection, providing context on when this tool is appropriate. However, it does not explicitly mention when not to use it or name direct alternatives, so it falls short of a 5.

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