read_thread

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

With no annotations, the description carries the full behavioral burden. It adds useful context by stating chronological ordering, attachment lists, and that message content is untrusted data, but it does not disclose permissions, pagination/truncation behavior, or what happens when max_messages is omitted or exceeded.

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 sentences with no wasted text. The core purpose is front-loaded, and the security warning is concise and relevant.

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 read tool with no output schema and no annotations, the description adequately conveys the return shape and a key security caveat. It remains incomplete on max_messages semantics and pagination/truncation behavior, which an agent would need to invoke it correctly.

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 only 50%: thread_id is documented, but max_messages has no description beyond min/max constraints. The tool description does not mention max_messages at all, so it fails to compensate for the schema gap or explain default/limit behavior.

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: reading a Gmail thread, with chronological ordering and attachment lists. It is clear enough to distinguish from sibling tools like read_email by resource, though it does not explicitly name when to prefer this over read_email.

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 implies that this tool is used to read a Gmail thread, but it gives no explicit guidance on when to use it versus read_email, list_emails, or read_draft. There are no exclusions, prerequisites, or alternative-routing instructions.

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