List Messages accounts with IDs, service types, and connection states to verify which services are available or connected. Read-only.
Read-only: list Messages accounts (also called services), IDs, service types, and connection states. serviceType is null if macOS does not expose it.
| Name | Required | Description | Default |
|---|---|---|---|
| limit | No | ||
| offset | No |
Changes observed during successful MCP inspections.
v3.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the 'Read-only:' prefix is redundant and earns no credit. The one genuinely additive detail is the edge case that serviceType is null when macOS does not expose it, which tells the agent not to treat null as an error.
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?
Two short sentences, front-loaded with the operation and its returned fields, with no padding. The only waste is the 'Read-only:' prefix that merely repeats the annotation.
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?
With no output schema, the description usefully names the returned fields and flags the nullable serviceType, which is good for a list tool. However it omits pagination semantics for the limit/offset pair and gives no hint about typical account counts or ordering, leaving an agent to guess at paging.
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% and the description never mentions limit or offset, so neither parameter's meaning (page size, pagination offset) nor the pagination behavior is explained anywhere beyond the raw min/max/default values. With two undocumented params the description does not compensate for the coverage gap.
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 ('list Messages accounts') and even enumerates the returned fields (IDs, service types, connection states), so an agent immediately knows what it gets. It never names a sibling or contrasts itself with apple_mail_list_accounts / apple_reminders_list_accounts, so it falls just short of full sibling differentiation.
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?
No when-to-use guidance, no prerequisites, and no mention of the near-identical account-listing tools for Mail and Reminders. An agent has to infer from the tool name alone that this is Messages-specific and should be called before addressing chats or sending messages.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.