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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description does add a genuine behavioral trait beyond annotations: results are filtered by folder access and may be smaller than the page size. However, the mention of 'page size' is confusing given no paging parameter exists in the schema, and nothing is said about result shape or ordering.

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?

Two sentences, purpose front-loaded, and every clause carries information. The second sentence is slightly convoluted ('fewer than the page size when folder rules apply') but is not padding.

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?

For a two-parameter read-only search with no output schema, the description covers purpose and one useful access-filtering caveat, but omits what a result item contains and how results are ordered or limited. Adequate but with clear gaps for an agent that must interpret the response.

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 coverage is 50%: mailbox is fully documented in the schema (including a pointer to list_authorized_mailboxes), while query has no description. The description only clarifies that query is free text, adding little beyond what the schema already conveys. Baseline 3 is appropriate.

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?

States a specific verb and resource ('Search one account's OneDrive for files and folders') and narrows scope to text-query matching, which implicitly separates it from list_onedrive_items. It does not name any sibling explicitly, so the differentiation is inferential rather than stated.

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 phrase 'matching a text query' implies you reach for this tool when you have a search term rather than a full listing, but the description never states when to prefer it over list_onedrive_items (or search_gdrive_items for the other drive). Usage is implied, not prescribed.

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