ensure_inbox_rule

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

Annotations already indicate idempotent and non-destructive. The description adds details: 'zero write calls if already correct', 'never duplicates rules or folders', and the write-enablement condition. This enriches understanding beyond annotations.

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 concise and well-structured, with a bold introductory statement followed by details. The Args block is efficiently formatted. Minor redundancy with 'THE ONLY WRITE TOOL' emphasis, but overall effective.

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 simple operation with 3 params and no output schema, the description covers purpose, idempotency, and enablement condition. However, it lacks information about error handling, return values, or what happens if the folder creation fails. This is adequate but not fully complete.

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?

Even though schema description coverage is 0%, the description provides an Args block with clear explanations: name as idempotency key, from_contains as substring match, move_to_folder as target folder. This fully compensates for the schema's lack of descriptions.

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 tool's function: 'Idempotently provision one inbox rule' and explains it moves messages matching 'from_contains' to 'move_to_folder'. It also distinguishes itself as 'THE ONLY WRITE TOOL' among siblings, establishing clear identity.

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 explains idempotency and safety of repeated runs, and notes the environment variable requirement for enablement. However, it does not explicitly compare against sibling tools like 'list_inbox_rules' or provide when-not-to-use guidance, though the 'only write tool' hint provides context.

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