get_thread

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

Annotations already indicate read-only, non-destructive, and closed-world behavior. The description adds valuable context beyond annotations by specifying that it returns nested thread trees with parent messages and replies in order, which clarifies the output structure and ordering behavior not covered by 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 front-loaded and concise, with two sentences that efficiently convey the tool's purpose and output. Every sentence adds value without redundancy, making it easy for an agent to quickly understand the tool's function.

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 the tool's moderate complexity (3 parameters, no output schema), the description is mostly complete. It explains the core functionality and output format, but lacks details on error handling, performance limits, or how it integrates with sibling tools. With annotations covering safety, it provides sufficient context for basic use.

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 fully documents parameters. The description does not add meaning beyond the schema, such as explaining how parameters interact (e.g., combining message_guid and contact) or providing examples. Baseline 3 is appropriate as the schema handles parameter documentation adequately.

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's purpose with specific verbs ('reconstruct', 'returns') and resources ('iMessage reply threads', 'nested thread trees'), distinguishing it from sibling tools like get_conversation or get_message_effects by focusing on thread reconstruction rather than general conversation retrieval or message metadata.

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 usage for thread reconstruction but does not explicitly state when to use this tool versus alternatives like get_conversation or search_messages. It provides context (using thread_originator_guid) but lacks explicit guidance on exclusions or prerequisites, such as whether it works for group chats or specific message types.

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