Read a text file from OneDrive

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description still adds real behavioral detail beyond them: metadata is read before the content, binary formats are rejected with an explanation rather than failing opaquely, and content is truncated with a marker. That is exactly the value-add expected when annotations carry the safety signal.

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?

Three sentences, each load-bearing: what it returns, the refusal rule, and the alternative for unsupported formats. Return behavior is front-loaded and the routing hint closes the paragraph with no filler.

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?

With no output schema, the description carries the return contract itself and does so ('as a string, truncated to maxChars'), plus the failure mode for binary input and the downstream alternative. An agent has everything needed to call it correctly and to recover from a refusal.

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 both itemId and maxChars are already documented, including the 20000 default and the truncation marker. The description restates the maxChars default but adds no new syntax, format, or edge-case meaning, so the baseline 3 applies.

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?

Names a specific verb and resource ('Returns the contents of a text-like OneDrive file') and enumerates the exact formats covered (plain text, Markdown, CSV, JSON, XML, source code, config). It also carves out the boundary against files_parse_document, so an agent can distinguish it from siblings without opening any schema.

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?

Explicitly states when-not to use it (binary formats — PDFs, images, Office documents, archives, media — are refused) and names the correct alternative for those cases (files_parse_document for .docx/.xlsx/.pptx/.pdf). Both the routing condition and the destination tool are given, leaving nothing to inference.

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