gemini_upload_file

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

Annotations indicate readOnlyHint=false and openWorldHint=true, aligning with the write operation described. The description adds behavioral details: 'upload once,' reusability, and token cost of data_base64. It does not contradict annotations.

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 front-loaded with the main purpose and keywords. It is slightly long but every sentence adds value, covering usage, parameters, and behavioral notes. Minor redundancy (e.g., 'reuse across calls' repeated) but overall efficient.

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 no output schema, the description clearly states the return value (file_uri as files/<id>). It covers input sources and expiration. Missing details on error handling or size limits (except in url param), but for a file upload, this is sufficient.

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%, but the description adds significant value: it explains that exactly one of url, data_base64, or path must be provided, clarifies the confirm parameter's requirement, and warns about token cost for data_base64. This goes well beyond the schema's descriptions.

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 Gemini Files API and returns a reusable file_uri. It lists supported file types (image, video, audio clip) and distinguishes from siblings like gemini_list_files or gemini_image_generate by focusing on upload-only functionality.

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 explicit use cases: upload files to avoid base64 tokens and for reusability across calls. It mentions expiration (~48h) but does not explicitly state when not to use this tool or name alternative tools. However, the sibling context shows no direct upload alternative, so the guidance is adequate.

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