create-mail-rule

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

Annotations (destructiveHint=true, readOnlyHint=false) already establish this is a mutating operation, and the description does not contradict them. Beyond annotations, it enumerates the eight supported actions (moveToFolder, copyToFolder, forwardTo, forwardAsAttachmentTo, delete, markAsRead, markImportance, stopProcessingRules), giving the agent concrete knowledge of what the tool can do.

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 core purpose is front-loaded in the first sentence, followed by a compact tip and example. It is not verbose and every element (example, action list) earns its place, though the action list could arguably live in the schema.

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 tool with a deeply nested body object, the description covers the actions fully and gives a representative conditions example. It does not enumerate all possible conditions, but the schema already documents those, so the description adequately complements the structured data.

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 80%, so a baseline of 3 applies, but the description adds genuine value by providing a complete inline example payload (displayName, sequence, isEnabled, conditions.fromAddresses, actions.moveToFolder) that clarifies the nested structure beyond what the schema alone communicates.

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 states a specific verb+resource ('Create a messageRule object') and explains the rule's behavior (Outlook carries out actions on inbox messages matching conditions). This clearly differentiates it from siblings like create-mail-folder, update-mail-rule, and list-mail-rules.

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 TIP section gives actionable guidance: use the Inbox folder ID from list-mail-folders, and it shows a representative body payload. It doesn't explicitly state when not to use this tool or name update-mail-rule as the alternative for modifying existing rules, but it does point the agent to the correct folder-ID source.

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