list_accounts

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

The readOnlyHint annotation already covers the safety profile, so the description is free to spend its words elsewhere, and it does: it enumerates the returned fields {id, name, user_name, account_type, email_addresses, enabled} and flags `name` as the canonical handle. With no output schema present, that return-shape disclosure is genuinely additive; it only lacks notes on ordering or whether disabled accounts are included.

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 plus a compact return-field list, with the purpose front-loaded and zero filler. Every sentence carries information the agent can act on.

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 no-argument read tool this is close to complete: it says what it lists, what comes back, and how to reuse the `name` handle. Minor remaining gaps are ordering and whether the list includes disabled accounts, which matters given the `enabled` field is returned.

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?

The tool takes zero parameters, so the baseline is 4 and there is no parameter semantics for the description to compensate for. The field-by-field return listing adds meaning beyond the empty schema without wandering into irrelevant detail.

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 opens with a specific verb and resource: "List every account configured in Apple Mail." That is unambiguous and distinct from siblings like list_mailboxes or list_attachments by resource alone, though it never explicitly contrasts itself with them.

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?

There is no explicit when-to-use or when-not-to-use guidance and no named alternative. The one implicit usage hint is that the `name` field is the canonical handle to pass as `account` to other tools, which gives the agent downstream context without ever stating the conditions that select this tool.

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