mail_thread

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

No annotations are provided, so the description carries the full behavioral burden. It usefully discloses that thread grouping works by subject-line matching, which can cause false groupings or omissions. Beyond that, it says nothing about ordering, permissions, or whether bodies/attachments are included, so it is only moderately transparent.

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 two short sentences, front-loaded with the purpose and then the mechanism. It is efficient and wastes little space. A slight overstatement—'all emails' when a default limit of 30 exists—keeps it from a perfect score.

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 two-parameter retrieval tool with no output schema, the description covers the core action and a key behavior. It still omits likely relevant context such as result ordering, failure modes when no thread is found, and the relationship to sibling search tools, so it is only minimally complete.

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 fully documents both file_path and limit. The description adds no parameter-level detail, making the baseline 3 appropriate.

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 clear verb and resource: 'Get all emails in a conversation thread.' It also adds a mechanism ('matching subject lines'), making the scope concrete. However, it does not differentiate from siblings like messages_conversation or mail_search, so 4 rather than 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?

There is no explicit when-to-use guidance, no conditions for choosing this tool over alternatives, and no exclusions. The implied use case is retrievable from the name and first sentence, but the description does not help an agent route between this and similar thread/search tools.

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