list_rules

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

With no annotations, the description carries the full burden and delivers real behavioral context: rules execute on Microsoft's servers and persist independently of this server, read_only rules cannot be modified via the API, and the required permission is disclosed along with the fact that the error message reports it. It stops short of describing result size, empty-list behavior, or pagination.

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?

Four short sentences, each contributing distinct information, with the what/order/contents front-loaded before the operational caveats. Minor polish issue: the third sentence starts with a lowercase 'read_only', which slightly blurs the boundary between the returned data and the constraint.

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 zero-parameter read tool with no output schema, the description supplies everything needed: what is returned, in what order, that conditions and actions are included, where the rules execute, and what permission is required. Nothing an agent needs in order to call it correctly is missing.

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?

The tool takes zero parameters, so the baseline is 4 and there is no schema semantics for the description to add or omit. Nothing about the parameter surface is misleading or under-specified.

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 names the specific resource (inbox rules Outlook applies to arriving mail) and states the payload shape (run order, conditions, actions), which is enough to distinguish it from create_rule/update_rule/delete_rule. It never uses an explicit verb like 'list' or names a sibling, so 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?

Usage is implied by the read-only framing and the permission prerequisite ('Needs the MailboxSettings.ReadWrite permission'), but there is no explicit when-to-use or when-not-to-use guidance, and no routing against suggest_rules, create_rule, or update_rule. An agent can infer this is the inspection step before mutating rules, but must do the inferring.

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