List Threads

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

Annotations already declare readOnly, idempotent, openWorld and non-destructive behavior, so the safety profile is covered. The description usefully adds that results are thread-level summaries rather than full messages, but says nothing about ordering defaults, result payload shape, or rate/latency behavior beyond that single trait.

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 short sentences, front-loaded with the purpose and followed by the pagination instruction. Nothing is redundant or padded.

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?

With 11 optional parameters, rich annotations and an output schema, the definition is callable as written, but for a tool this configurable the description is thin — it omits what a returned thread contains and how filters interact (e.g., whether q searches message bodies). Adequate but with clear room to do more.

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% with 11 well-documented parameters, so the schema carries the burden and a 3 is the baseline. The description only echoes the cursor pattern ('next_cursor from the previous response'), adding no filtering or sorting semantics beyond what the schema already provides.

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 ('scan conversation threads') and scopes it as a lightweight listing that does not load message bodies, which distinguishes it from message-fetching operations. It stops short of naming the sibling tools (get_thread, list_thread_messages) that would be the alternative, so a 4 rather than a 5.

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 contrast with 'loading every message' implies when to prefer this tool over thread/message retrieval, and there is explicit pagination guidance ('Continue with next_cursor only when additional threads are needed'). However, no alternative is named and there is no guidance on when to use it versus mailbox_list_messages or a search tool.

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