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

Annotations declare it is a non-read-only, non-destructive write with no open-world side effects, and the description goes beyond them by disclosing that the rule persists server-side in Exchange and keeps firing after the session ends. It omits permission requirements and any limits on rule count or duplicate names.

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, zero filler, with the core action and effect front-loaded and the required-condition caveat at the end where it is easiest to act on.

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?

Covers action, persistence behavior, and the minimum-condition rule for an 8-parameter write tool; annotations already carry the safety profile and no output schema exists, so return values need not be explained. Minor gaps: no mention that the mailbox must be connected (only hinted in the schema) or of duplicate-name handling.

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 baseline is 3. The description adds a cross-parameter constraint not expressed in the schema (no anyOf/oneOf present): at least one match condition must be supplied, and it names the sender/subject/destination roles, which maps the fields to the described behavior.

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+resource ("Create an inbox rule") and the effect (auto-move matching mail into a folder). Saying it "Runs server-side in Exchange" implicitly separates it from the Gmail counterpart create_gmail_filter, but no sibling is named explicitly.

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?

Adds a real prerequisite ("At least one condition is required"), which tells the agent when the call is valid. However, it never says when to prefer this over create_gmail_filter/create_mail_folder or lists the alternatives, so usage is only implied.

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