upload_file

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

Without annotations, the description discloses automatic MIME type detection and environment variable requirements. However, it does not cover other important behavioral aspects such as whether existing objects are overwritten or what error behavior might be expected.

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?

Two clear, front-loaded sentences with no redundant information. Every sentence contributes meaningful content.

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?

Adequate for a simple upload tool, covering the main action, prerequisites, and a behavioral detail. Could be improved with mention of return values or error handling, but the absence of an output schema makes the current level acceptable.

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 schema already covers both parameters with descriptions. The description adds no additional parameter semantics beyond what the schema provides, making the baseline score appropriate.

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?

Clearly states it uploads a file to an S3 bucket with a specific verb and resource. No ambiguity about the action.

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?

Provides prerequisite context (required environment variables) but does not discuss when to use this tool versus alternatives or any exclusions. Since there are no sibling tools, the lack of alternatives is understandable but not fully addressed.

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