Apple Prepare Communication

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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds that the tool does not send anything but returns a recommended mail or messages target, which clarifies its non-mutating, advisory behavior. This goes beyond the annotations in explaining the tool's purpose.

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 a single sentence that front-loads the core functionality and avoids filler. It is concise and readable, though it slightly crams multiple actions into one sentence without clear section separation. No words are wasted.

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?

The description covers the main use case and notes the tool is a pre-send step, but it leaves ambiguity around how 'preferred_channel' influences the result and what happens when resolution fails or a channel is unavailable. The output schema exists and may fill these gaps, but its contents are not shown in the provided context.

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 0%, so the description must carry the explanatory burden. It mentions 'recipient' and 'channels' but gives no additional meaning for the optional 'preferred_channel' parameter, such as whether it overrides the recommendation or merely biases it. There are no enums or examples to help an agent understand the expected values.

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 uses concrete verbs ('Resolve', 'evaluate', 'return') and names the resource ('recipient', 'channels'), clearly indicating this tool prepares communication by resolving a contact and recommending a channel. It distinguishes itself from sending and previewing, though it does not explicitly name sibling alternatives.

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 phrase 'before sending' implies a clear temporal position in the workflow, suggesting this tool is a pre-send step. However, it does not explicitly state when to choose this tool over alternatives like apple_preview_communication or apple_send_communication, nor does it mention anything about skipping it.

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