Upload File

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

The description enriches beyond annotations by detailing upload strategies (auto/direct/presign), size thresholds (<10MB), endpoints (/v1/files/upload, presigned S3), and supported formats. This provides deep behavioral insight, especially since annotations only indicate basic safety hints.

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 well-structured with a clear opening purpose, usage note, supported formats list, and parameter details. Every sentence serves a purpose, and it is concise without unnecessary filler.

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?

Despite no output schema, the description states that the tool returns a URL and how to use it. It covers parameter semantics, format support, internal strategy details, and usage context, making the tool fully understandable without needing to inspect schema or annotations.

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 baseline is 3. The description adds meaningful detail for the strategy parameter by explaining the behavior and trade-offs of each enum value (e.g., 'auto: small files go via direct upload, larger via presigned S3'). This goes beyond the schema's enum list.

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 local file to XBrush CDN and returns a URL, with specific verb and resource. It also explains the purpose of the returned URL in other XBrush tools, distinguishing it from sibling tools that generate or process media.

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 indicates when to use the tool ('Upload a local file ... Use the returned CDN URL as image_url or video_url in other XBrush tools'), providing clear context. It does not explicitly mention alternatives or when not to use it, but the context is sufficient for an upload utility.

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