get_thread

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

Annotations declare readOnlyHint, openWorldHint, and idempotentHint, indicating safe non-destructive read behavior. The description adds minimal behavioral context beyond grouping logic, but does not contradict annotations.

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 a single concise sentence, directly stating the tool's purpose. While brief, it is front-loaded and lacks unnecessary words. A bit more detail would be justified but current length is efficient.

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 an output schema present, the description does not need to detail return format. However, it omits any mention of default behavior (e.g., ordering, inclusion of duplicates). Still, minimal completeness is achieved for the given complexity.

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 low (25%). The description does not elaborate on any parameter semantics, leaving the agent without additional meaning beyond the schema's own descriptions (e.g., uid 'Any message UID in the thread').

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 the tool groups messages based on Message-ID/References/In-Reply-To headers, which precisely identifies the action and resource. It effectively distinguishes from siblings like read_email (single message) or search_emails (query-based).

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 no guidance on when to use this tool versus alternatives such as read_email or search_emails. It lacks any context about prerequisites, conditions, or exclusions.

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