update-mail-rule

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

Annotations already provide readOnlyHint=false and destructiveHint=true, indicating mutation. The description adds that changes are saved (implying persistence) and recommends partial updates. However, it does not elaborate on results, error conditions, or the read-only property, leaving the agent somewhat in the dark about edge cases.

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 extremely concise: two sentences plus a tip. It is front-loaded with the core purpose, followed by a helpful tip. Every sentence provides essential guidance with no redundancy or filler.

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 complexity of the input schema (nested objects, many properties) and the absence of output schema, the description provides sufficient context: what the tool does, how to use it (partial update, folder ID), and a common use case. It does not cover all edge cases, but the schema and annotations fill significant gaps.

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 80% schema description coverage, the schema already documents parameters well. The description adds value by advising to 'Send only the properties to change' and giving a concrete example ({ isEnabled: false }), which clarifies usage beyond the schema. It also mentions folder ID context for the mailFolderId parameter.

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 purpose: 'Change writable properties on a messageRule object and save the changes.' It uses a specific verb ('update') and resource ('messageRule object'), and distinguishes from siblings like create-mail-rule and delete-mail-rule by focusing on modification of existing 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 description explicitly says when to use: 'Updates an existing message rule.' It provides practical guidance: 'Use the Inbox folder ID (get it from list-mail-folders) for inbox rules. Send only the properties to change.' It gives a common use case example, but does not explicitly exclude scenarios or mention alternative tools.

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