Grok MCP

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

Annotations provide readOnlyHint=true, indicating a safe read operation. The description adds valuable behavioral context beyond this: it specifies UTF-8 decoding with replacement for invalid sequences, truncation to max_bytes, and appends a truncation note when content exceeds the limit. This clarifies how the tool handles encoding and large files, though it does not mention rate limits or authentication needs.

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 front-loaded with the core purpose in the first sentence, followed by behavioral details and a structured Args/Returns section. Every sentence adds value—no redundancy or fluff—and the formatting enhances readability without wasting space. It efficiently conveys necessary information in a compact form.

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 moderate complexity (2 parameters, no output schema), the description is largely complete: it covers purpose, behavior, parameters, and return values. However, it lacks explicit usage guidelines versus siblings and does not mention potential errors (e.g., invalid file_id) or performance considerations, leaving minor gaps in full contextual understanding.

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 0%, so the description fully compensates by explaining both parameters: 'file_id' as 'ID of the uploaded file' and 'max_bytes' as 'Maximum bytes to return' with a default value. It also clarifies that output is truncated to max_bytes, adding meaning beyond the schema's basic type definitions. However, it does not detail constraints like valid ID formats or byte range limits.

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 ('Download the raw content'), resource ('of an uploaded file'), and output format ('as text'), distinguishing it from sibling tools like 'get_file' (which likely returns metadata) or 'upload_file' (which uploads rather than downloads). The verb+resource combination is precise and unambiguous.

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 usage by mentioning truncation to avoid overwhelming responses, but it does not explicitly state when to use this tool versus alternatives like 'get_file' (which might return metadata) or 'chat_with_files' (which processes files in chat context). No exclusions or prerequisites are provided, leaving usage context somewhat open to interpretation.

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