Grok MCP

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

Annotations declare readOnlyHint=true, indicating a safe read operation. The description adds valuable context beyond this: it specifies that the file must be 'uploaded' (implying a prerequisite), mentions the source of file_id ('returned by upload_file'), and describes the return format ('Markdown block with...'). This enhances understanding of the tool's behavior.

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 perfectly structured and concise: a clear purpose statement followed by 'Args:' and 'Returns:' sections. Every sentence earns its place by providing essential information without redundancy. It is front-loaded with the core functionality.

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 the tool's low complexity (1 parameter, no output schema), the description is complete. It covers purpose, parameter semantics, return format, and prerequisites. With annotations handling safety, no additional context is needed for effective use.

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 0% description coverage, so the description carries the full burden. It explicitly defines 'file_id' as 'ID returned by upload_file', adding crucial semantic meaning that the schema lacks. This compensates fully for the schema's deficiency.

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 specific action ('Fetch metadata') and resource ('for a single uploaded file'), distinguishing it from siblings like 'get_file_content' (which retrieves file content) and 'list_files' (which lists multiple files). The verb 'fetch metadata' precisely defines what the tool does.

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 clear context for when to use this tool: to retrieve metadata for a single file identified by its ID. It implicitly distinguishes from 'list_files' (for multiple files) and 'get_file_content' (for file content), but does not explicitly name alternatives or state when not to use it.

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