list_inbound_messages

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions ordering ('newest first') and optional filters, but omits important behaviors such as pagination semantics, error handling, authorization requirements, or return format. For a listing tool with no output schema, this is insufficient for an agent to predict consequences reliably.

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 a single, efficient sentence. It front-loads the primary purpose and includes the ordering detail. There is zero redundancy or filler, making it appropriately concise and well-structured.

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 4 parameters, no output schema, and no annotations, the description is too sparse. It does not specify the response shape (e.g., whether it returns full messages or summaries, pagination metadata), nor does it mention potential side effects or prerequisites. An agent would lack critical context to correctly interpret results or handle edge cases.

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 coverage is 100% and each parameter has a basic description. The tool description adds the notion that mailboxId and keyword are filters, but does not elaborate on syntax, default values, or interplay. Since the schema already documents parameters, the description adds minimal value beyond confirming their filter role, keeping the score at baseline 3.

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 'List' and the resource 'inbound (received) email messages', with explicit ordering 'newest first'. This distinguishes it from siblings like get_message (single message), list_mailboxes, and send_email. The purpose is unambiguous and self-contained.

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 does not provide any guidance on when to use this tool versus alternatives such as list_threads or check_new_messages. It implies usage for listing messages but gives no exclusions or conditions. The only usage hint is the optional filtering, which is more about parameters than tool selection.

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