list_threads

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

With no annotations, the description carries the transparency burden. It discloses pagination behavior (next_cursor), default ordering, response fields (subject, message count, last activity, snippet), and the necessity of filters. It does not mention permissions or rate limits, but for a read-only listing operation, this is sufficient.

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 well-structured with a brief introduction, return format note, usage requirement, and an Args list. Every sentence provides value, and there is no redundancy or fluff.

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?

The description is complete for a list operation. It covers key behavior (pagination, filtering, sorting), return summary fields, and parameter constraints. Since an output schema exists, it need not describe every return field, but it still gives the essential information for correct usage.

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 0%, but the description fully compensates by explaining each parameter's purpose and constraints: inbox_id for filtering, domain_id as alternative, limit range 1-100, cursor for pagination, and order with desc/asc defaults. This adds significant meaning beyond the schema's type-only definitions.

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 email threads (conversations) with pagination,' which is a specific verb+resource. It differentiates from sibling tools like search_threads and get_thread_messages by focusing on listing with pagination and summarizing thread attributes.

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 explicit usage context: returning thread summaries, pagination via next_cursor, and the requirement to provide at least one of inbox_id or domain_id. It does not explicitly discourage use of alternative tools, but the pagination and filter requirements are clear usage guidelines.

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