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

The description discloses the return values (key, upload_url, expires_in) and details the upload flow, adding context beyond annotations. While annotations already indicate non-destructive and open-world behavior, the description adds the upload host and validity period. No contradictions.

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 somewhat long (4 sentences) but each sentence serves a purpose: stating the main action, describing the return value and flow, and providing usage guidance. It is well-structured and front-loaded with the core purpose.

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 parameters and no output schema, the description covers the essential aspects: purpose, flow, and conditional usage. It could mention error handling or idempotency, but it is adequate for the tool's simplicity.

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 has no parameters, so schema description coverage is effectively 100%. The description does not need to add parameter meaning, as there are none to document.

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 it creates a temporary file upload URL for sandboxed environments, with a specific verb and resource. It distinguishes itself from local server usage by explicitly stating when to use and when not to use, differentiating from sibling tools.

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 guidance on when to use (remote MCP server) and when not to use (local stdio server), and offers an alternative (pass local file paths directly). It also mentions the need to whitelist the upload host, which is crucial for correct invocation.

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