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

With no annotations, the description carries the full burden and does disclose a meaningful trait: the rule executes server-side in Exchange and persists after this tool is unavailable. It also flags the non-obvious requirement that at least one condition must be supplied, though it does not discuss permissions, limits, or response behavior.

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 short sentences with no filler; the core action is front-loaded, followed by the persistence trait and the validation caveat. Every sentence earns its place.

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 an 8-parameter create tool with fully documented parameters and no output schema, the description covers action, persistence, and the central validation rule. It could add that the rule applies to future mail or that it can be managed via delete_inbox_rule/list_inbox_rules, but nothing essential is missing for a competent agent.

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 100%, so the schema already documents every parameter. The description adds value by encoding a cross-parameter constraint not visible in the schema's required list: at least one condition is required, and by summarizing the sender/subject criteria.

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 first sentence names a specific verb and resource ('Create an inbox rule') and states the behavior: automatically moving incoming mail matching sender or subject criteria into a folder. This clearly differentiates it from list/delete inbox rule tools and Gmail filters.

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?

It implies usage via 'Runs server-side in Exchange' and persistence, which suggests using it when a rule must survive independently of this tool. However, it never explicitly contrasts it with sibling alternatives such as create_gmail_filter or states when not to use it.

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