list_mailbox_threads

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

With no annotations, the description carries the full burden. It usefully discloses that each row is a thread with its latest message, but says nothing about ordering, whether reading marks messages as read, permissions required, or how pagination behaves beyond the schema's limit/offset fields.

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?

A single front-loaded sentence with no filler; the resource and the returned shape (threads with latest message) are stated immediately.

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 read-only listing tool with fully documented parameters, this is adequate but thin: no ordering guarantee, no note about thread-level pagination, and no mention of what happens with an invalid or empty mailbox_id.

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 the schema already documents mailbox_id, limit, and offset. The description adds no extra semantics such as default/max limit, offset ordering, or thread-count behavior, so the baseline of 3 applies.

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 states a specific verb and resource ('list conversation threads') and scopes it to an agent mailbox, plus discloses a key characteristic (latest message per thread). It is distinguishable from list_emails and list_mailboxes by name and by the 'thread' concept, though it never explicitly contrasts with the thread-reading siblings.

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?

There is no guidance on when to choose this over list_emails, read_mailbox_messages, or search_mailbox, all of which return mailbox content. The agent must infer from the tool name whether thread-level or message-level listing is wanted.

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