list_inbound

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

Annotations already declare readOnlyHint=true, so the description doesn't need to establish safety. It adds useful behavioral details such as 'newest first' and the held-message nuance, but does not describe pagination behavior or result shape. This is comparable to a baseline where annotations cover the core behavioral profile.

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 concise sentences with no filler. The core purpose and ordering are front-loaded, and the scope expansion about held messages is placed second without wasting words.

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 read-only list tool with five fully documented optional parameters and no output schema, the description provides enough context: what is listed, ordering, and which message categories are included. It does not describe the output envelope, but that is a minor gap for a simple list operation with no output schema.

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 description coverage is 100%, so all five parameters are already documented. The description adds no additional parameter-level meaning, which matches the baseline of 3 for fully covered schemas.

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?

States a specific action and resource: 'List inbound and held messages, newest first.' It clearly defines the scope, including the non-obvious inclusion of outbound mail held by the spam filter, which distinguishes it from sibling tools like get_inbound or list_emails.

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?

Provides clear context on what the tool covers: inbound-route mail and spam-filter-held outbound mail. It does not explicitly name alternatives or state when not to use it, but the coverage description is enough to guide selection.

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