Microsoft 365 MCP Server

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, indicating a safe, read-only operation with potentially large results. The description adds valuable behavioral context beyond this: it clarifies the scope limitation (root-level folders only), mentions hidden folder handling, and implies pagination/traversal needs. While it doesn't detail rate limits or auth specifics, it provides meaningful operational constraints that annotations alone don't cover.

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 appropriately sized (four sentences) and front-loaded with the core purpose. Each sentence adds value: the first states the action, the second clarifies inclusion rules, the third explains scope limitations, and the fourth provides alternative guidance. There's no redundant information, though it could be slightly more streamlined by combining related points about hidden folders and traversal.

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 (12 parameters, no output schema), the description provides strong contextual completeness. It covers the tool's scope, limitations, and alternatives, which annotations and schema don't address. While it doesn't explain return values (no output schema exists), it sufficiently guides usage for a read-only listing operation. The main gap is lack of explicit pagination or performance guidance, but overall it's well-rounded.

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?

With 100% schema description coverage, the input schema fully documents all 12 parameters. The description only mentions one parameter ('includeHiddenFolders') explicitly and implies pagination through the traversal discussion. It adds minimal semantic value beyond the schema, which already describes each parameter's purpose. The baseline score of 3 reflects adequate but not enhanced parameter understanding from the description.

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 ('Get the mail folder collection'), resource ('directly under the root folder of the signed-in user'), and scope ('does not return all mail folders in a mailbox, only the child folders of the root folder'). It explicitly distinguishes this tool from the alternative approach of traversing child folders separately, making it distinct from sibling tools like 'list-mail-folder-messages' or 'list-mail-messages'.

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 provides explicit guidance on when to use this tool ('does not return all mail folders... only the child folders of the root folder') and when to use alternatives ('To return all mail folders in a mailbox, each child folder must be traversed separately'). It also specifies the default behavior ('does not return hidden folders') and how to override it ('Use a query parameter includeHiddenFolders'), offering clear context for usage decisions.

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