gmail_read_thread

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

No annotations are provided, so the description must fully disclose behavioral traits. While 'Read' implies a non-destructive operation, the description does not explicitly state that the tool is read-only or safe. It also fails to describe what the output contains (e.g., full message bodies vs. metadata) or any side effects.

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, front-loading the purpose and immediately providing actionable parameter guidance. Every word earns its place, with no fluff or repetition.

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?

Given 5 parameters, no output schema, and no annotations, the description lacks essential context. It does not explain what data is returned (e.g., full message content, headers, or metadata), how pagination works beyond max_messages, or how this tool differs from gmail_batch_read_messages. The agent would need to infer too much.

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?

The schema covers 80% of parameters with descriptions. The description adds meaningful context for thread_id ('legacy behavior'), id_type ('interpret as message or thread'), and max_messages ('returns the most recent N messages'), which goes beyond the schema. This compensates for the undocumented max_messages parameter.

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 the verb 'Read' and resource 'Gmail thread', making the primary purpose clear. However, it does not explicitly distinguish from sibling tools like gmail_read_message or gmail_batch_read_messages, which could lead to confusion about whether to use this tool vs alternatives.

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 parameter guidance ('Pass thread_id for legacy behavior, or id plus id_type=message/thread') but lacks explicit advice on when to use this tool versus alternatives (e.g., gmail_read_message for single messages). No context is given about prerequisites, limitations, or typical use cases.

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