list_accounts

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

With no annotations provided, the description carries full responsibility. It accurately portrays the read-only nature of listing accounts and explains the output's significance. While it doesn't cover edge cases or rate limits, it is transparent about the core behavior.

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 extremely concise (two sentences) yet fully informative. The first sentence states the primary purpose immediately, and the second adds essential context. Every word contributes without redundancy.

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?

Given the tool has no parameters and an output schema exists (as indicated by context signals), the description is complete. It explains what the tool does and why the output matters, leaving no critical gaps for an agent to select or invoke it 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 input schema has 0 parameters, and schema description coverage is 100%. Per guidelines, a tool with no parameters receives a baseline of 4. The description does not need to add parameter-level detail because there are none.

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 is specific: 'List CallRail accounts accessible to this API key.' It clearly identifies the action (list), the resource (accounts), and the scope (accessible to this API key). It also explains the critical role of the returned `id` field, distinguishing this tool from other list tools such as list_companies or list_calls.

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 context about typical usage ('Most users have one account per agency') and hints that it is a prerequisite for other tools via the auto-resolved account_id. However, it does not explicitly state when to use or avoid this tool, nor does it compare it directly to alternatives.

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