list_mail_accounts

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds useful behavioral context beyond annotations: results are scoped to the current user and include aliases, clarifying what 'all accounts' means.

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 concise and front-loaded with the core action. The only minor redundancy is that the return format is stated twice: once as 'returns the accounts and their aliases' and again in the structured 'Returns' block. This is not harmful but slightly repetitive.

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 simple zero-parameter read-only tool, the description covers scope, output structure, and downstream usage. With annotations and an output schema already present, nothing material is missing for an agent to select and invoke this tool correctly.

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 has no parameters, so parameter semantics are trivially satisfied. The description reinforces the output's purpose by explaining how the account ID will be consumed by downstream operations, which is helpful even without parameters.

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 clearly states the verb and resource: 'List all email accounts configured in Nextcloud Mail.' It also scopes the operation to the current user and distinguishes it from account-specific operations like list_mailboxes and send_mail.

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 description provides practical context by telling the agent that the returned account ID should be used to list mailboxes and send emails. It does not explicitly name alternatives or exclusions, but for a zero-parameter listing tool the guidance is sufficient.

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