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

Annotations already declare readOnlyHint=true, openWorldHint=false, destructiveHint=false, so safety is covered. The description adds that sharing links are returned and that the response carries a permissionId usable for revocation, but says nothing about pagination, ownership filtering, or permissions required to call it.

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?

A single tight sentence with no filler, front-loaded on the core action. 'an item' is slightly vague (file vs folder), but nothing is wasted.

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?

Adequate for a read tool whose annotations carry the safety profile and which has no output schema, and it does characterize the return (people, sharing links, permissionId). However the undocumented itemId parameter and absence of any pagination or scoping notes leave a real gap for correct invocation.

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 only 50%: 'mailbox' is documented in the schema (with a pointer to list_authorized_mailboxes) while 'itemId' has no description at all. The description adds no parameter meaning, so it fails to compensate for the undocumented itemId (file vs folder, drive-qualified ID expectations).

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 ('List everyone with access to an item') plus scope ('including any sharing links that already exist') and even flags a downstream field (permissionId). This is clearly distinguishable from list_onedrive_items (files) and list_gdrive_permissions (different service).

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?

Usage is only implied: the mention of 'the permissionId needed to revoke one' hints that this is the lookup step before unshare_onedrive_item. No explicit when-to-use, prerequisites, or named alternative is given, so the agent must infer the workflow.

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