get-thread

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

With no annotations, the description carries the full burden. It discloses the threading algorithm (References/Message-ID for imap: IDs, normalized subject otherwise) and specifies the returned fields. A minor gap is not explicitly stating that it is a read-only operation with no side effects, but the 'get' prefix and return summary make that reasonably clear.

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 compact and well-structured with clear 'Use when', 'Returns', and 'Do not use when' sections. Every sentence adds distinct value, and critical information is front-loaded.

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?

The description is complete for a read-only thread retrieval tool. It covers when to use, what it returns, how threading is determined, and what to use instead. The existing output schema further covers return structure, so the description does not need to duplicate that.

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 coverage is 100% (baseline 3), but the description adds valuable meaning by explaining how the 'id' parameter's imap: prefix changes the threading behavior. This goes beyond the schema's simple type/pattern description and helps the agent understand the underlying semantics.

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?

Description explicitly states the tool's function: given one message ID, retrieve the entire conversation it belongs to, ordered oldest-first. It clearly distinguishes itself from sibling tools by naming get-message and search-messages as alternatives when the user's need is different.

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?

Provides explicit 'Use when' and 'Do not use when' guidance, including specific alternatives (get-message, search-messages). It also clarifies the two threading modes based on ID format, which helps the agent decide when this tool is appropriate.

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