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

The description adds meaningful behavioral details beyond the annotations: base64 requirement, max file size, allowed types, and filename sanitization. Since annotations only declare readOnly=false and idempotent=false, these constraints provide valuable context, though the description does not disclose success responses or failure modes.

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 organized but redundant: the introductory paragraph is repeated almost word-for-word under '## When to use', and the parameter list duplicates schema descriptions. It could be condensed into a single, non-repetitive paragraph while preserving all key information.

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?

With four parameters and no output schema, the description covers input constraints and file type limits thoroughly, but it omits what happens after a successful upload (e.g., file ID, URL, or how to reference the file). This is a significant gap for an upload tool, despite the otherwise useful detail.

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?

The input schema already provides 100% parameter descriptions, so the baseline is 3. The description repeats these in a 'Parameters to validate before calling' section but adds only marginal emphasis (e.g., reinforcing base64 encoding and sanitization) without introducing new semantic meaning.

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 a file to the user's Drive and specifies key constraints (base64 encoding, 10 MB max, allowed types). However, it does not differentiate from sibling tools like send_file or get_file_url, so the purpose is clear but not uniquely distinguished.

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?

A 'When to use' section exists but it merely restates the same purpose without any guidance on when not to use this tool or which sibling to choose instead. No alternatives or exclusions are mentioned, leaving the agent without decision support.

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