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

No annotations are provided, so the description carries the full burden for behavioral disclosure. It does mention chunk size limits (100MB) and that chunkIndex is 0-based. However, it doesn't disclose upload completion semantics, whether chunked uploads assemble automatically, error handling, or whether uploads can overwrite existing files with same name.

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 compact and front-loaded with the core purpose in the first sentence. The two-sentence structure efficiently covers both upload modes. It's appropriately sized for the tool's complexity, though it could arguably be slightly more organized with separators between the single and chunked instructions.

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 essentials for a 5-param, 2-required-param upload tool with no output schema and no annotations. It documents the two usage modes and size limits. However, it lacks details on return values (what success looks like), prerequisites (auth requirements), and post-upload behavior.

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 100%, so each parameter already has documentation in the schema. The description does add value by explaining the logical grouping (single mode requires fileName+fileData; chunked adds chunkIndex+totalChunks), which clarifies the semantics beyond individual parameter descriptions. However, it doesn't add significant new meaning beyond what the schema conveys.

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 uploads an app file (APK/IPA) to the server, with a specific verb+resource. It also distinguishes between single and chunked upload modes. However, it doesn't explicitly differentiate from siblings like app_install or app_delete; while app_upload is clearly distinct by name and purpose, the description could note that this is the 'upload' step separate from 'install' or 'delete'.

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 specific guidance on how to choose between single vs. chunked uploads by specifying which parameters to provide for each mode. It also gives a concrete size threshold (max 100MB per chunk). However, it doesn't state when one should use chunked vs. single (e.g., 'use chunked for files >100MB'), only how to structure each mode.

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