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

Goes well beyond the annotations by disclosing the two-phase confirmation protocol (status='confirmation_required', action_id, plan_token, execution only after confirm_action) and stating that status is set to 'routed'. It also tells the agent the return value (created object's id). It does not clarify what happens to the original inbox item beyond the status flag (e.g., whether it disappears from list_inbox), which is the main residual gap given destructiveHint=true.

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?

Front-loads the action and parameters, then the confirmation protocol; nearly every sentence carries required information. The all-caps CONFIRMATION block is slightly heavy-handed and could be tightened without losing content.

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?

Despite no output schema and no annotation-level detail, the description covers the mutation effect, the required confirmation round-trip, the conditional parameter, and the return value. An agent has everything needed to call it correctly and interpret the response.

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 0% schema description coverage, the description fully compensates: it names 'inbox_id', 'to' with its 'note/task/event' values, the 'target' alias, and the conditional 'start_at' ISO datetime requirement for events. This covers every one of the four parameters with meaning the bare enum schema does not convey.

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 ('Turn one of the caller's inbox items into a personal object and mark it routed') and enumerates the resulting object types, so the agent knows exactly what the tool produces. The scope is narrower than a generic update tool, which distinguishes it from siblings like update_inbox_status.

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?

Gives clear operative context: the item must belong to the caller, the event case requires 'start_at', and the write only happens via confirm_action. It does not explicitly contrast with alternatives like update_inbox_status or add_to_inbox, but the confirmation workflow and preconditions are well stated.

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