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

Beyond annotations (destructiveHint, idempotentHint, readOnlyHint), the description discloses the cascade deletion of auto-reply cooldown rows, the required auth scope (message_update), and the exact failure modes: 404 rule_not_found for an unknown rule and 404 inbox_not_found for another account's inbox. These are concrete behavioral facts an agent needs before a destructive call.

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?

Purpose is front-loaded in the first clause, followed by prerequisites, inputs, return value, and error codes in that order. Every sentence carries decision-relevant information; the brief restatement of required inputs is the only mild redundancy.

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 destructive two-parameter mutation with an output schema, the description covers the cascade effect, auth scope, success shape, and both 404 cases. Nothing an agent needs in order to call it safely and interpret failure 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?

Schema description coverage is 100% and both parameters carry their own descriptions, so the baseline is 3. The description only restates that both inputs are required, adding no format, ownership, or resolution detail beyond the schema.

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 and resource ('remove one inbox rule') plus the scope of the cascade ('and its auto-reply cooldown rows'), which an agent could not infer from the tool name alone. It is cleanly distinguishable from sibling mutations like cooper_delete_inbox or cooper_update_rule by resource name.

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?

'Use this to remove one inbox rule' gives clear context for when to invoke it, and the cascade note signals a side effect that matters when deciding to delete vs. update. It stops short of naming alternatives (cooper_update_rule to disable, cooper_list_rules to resolve a rule_id), so no explicit when-not guidance is offered.

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