list_accounts

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

Annotations already declare readOnlyHint=true and destructiveHint=false, covering the safety profile. The description adds the 'Call this first' context, which is more of a usage guideline than a behavioral trait. It does not detail return format, but for a zero-parameter read-only list tool, the basic behavior is self-evident.

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 sentences: the first delivers the core function, the second adds essential usage guidance. No redundancy or filler; the most important information is front-loaded.

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 discovery tool, the description covers what it does, when to use it, and hints at the output ('available account names'). Annotations confirm safety. A minor gap is the lack of explicit response structure, but the description sufficiently implies the return value.

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 zero parameters, so the schema provides full coverage by definition. The description adds the expected output ('account names'), which is useful for setting expectations but not required for parameter understanding. Baseline 4 is appropriate.

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 'List all configured email accounts' with a specific verb and resource. It also distinguishes itself from sibling tools like list_mailboxes and list_emails by framing it as a discovery step for account names.

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 instruction 'Call this first to discover available account names for use with other tools' provides explicit temporal guidance and establishes the tool as a prerequisite. It does not name alternative tools or explicitly state when not to use it, but the context is clear.

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