upload_file

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

With no annotations, the description is the sole source of behavioral context. It discloses the return value and intended downstream use, but omits critical details such as file size limits, upload expiration, permission requirements, and error handling. This is a meaningful gap for a mutation tool.

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 sentences, zero fluff. The core purpose and return value are front-loaded. The '[Official API]' tag is slightly redundant but does not detract from overall conciseness.

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?

For a simple upload tool with three well-described parameters, the description is adequate. It links to send_file_as_user, giving enough context for invocation. However, it lacks nuance about file lifecycle and how it differs from upload_drive_file, preventing a perfect score.

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 the description adds no additional parameter meaning. The schema already documents file_path, file_name, and file_type with defaults and ranges. Baseline 3 is 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?

The description explicitly states the action 'Upload a file to Feishu' and specifies the return value (file_key) for use with send_file_as_user. This clearly distinguishes it from sibling tools like upload_drive_file, which serves a different purpose (permanent storage vs. message attachment).

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 implies when to use: when a file_key is needed for send_file_as_user. It does not explicitly mention alternatives like upload_drive_file for persistent storage, but the contextual signal is strong enough to guide selection for most agents.

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