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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the read-only behavior is covered. The description adds valuable behavioral context by explaining encoding auto-detection and fallback: 'Auto-detects UTF-8, falls back to Latin-1/Windows-1252 for legacy files.' This goes beyond what the annotations or schema communicate.

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 three sentences, front-loaded with the core purpose, then supporting details on formats and encoding, and ends with a concise pointer to the alternative. Every sentence adds value with no repetition or fluff.

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 output schema exists and annotations cover safety, the description fully covers the relevant operational context: supported file types, encoding behavior, and scope limitation. It also names the sibling tool for out-of-scope files, making the tool's placement in the overall ecosystem clear.

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 provides 100% coverage with descriptions for all four parameters, earning a baseline of 3. The description enhances parameter meaning by explaining the file type scope and the practical encoding fallback use case, which directly informs how to interpret 'encoding: auto' and the 'path' constraint.

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 opens with a specific verb and resource: 'Reads a text file from your OneDrive synced folder.' It clearly distinguishes itself from the sibling file_read tool by stating 'For files elsewhere on this Mac, use file_read,' and it lists supported file types, making its scope 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?

It explicitly states when to use this tool (files in the OneDrive synced folder) and when not to, with a direct alternative: 'For files elsewhere on this Mac, use file_read.' This satisfies the requirement for explicit usage guidance and alternative references.

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