messages_get_thread

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

With no annotations, the description carries the burden of behavioral disclosure. It correctly flags the requirement for Full Disk Access, indicating a read operation. However, it omits details on returned data format or potential side effects, leaving gaps for a tool reading sensitive data.

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 extremely concise—two sentences with no wasted words. The core purpose is front-loaded in the first sentence, and the second sentence adds a critical prerequisite.

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?

Despite low complexity, the description does not specify the output format or content (e.g., list of messages, metadata). The absence of an output schema makes this a notable gap for an AI agent deciding if the tool meets its needs.

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% with a clear description for the handle parameter. The tool description adds no additional parameter information beyond the schema, meeting the baseline for high coverage.

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 reads an iMessage/SMS thread by phone substring or email, identifying the specific verb and resource. It distinguishes from sibling tool messages_list_chats, which lists all chats, by specifying a targeted lookup method.

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 mentions a prerequisite (Full Disk Access) but does not explicitly state when to use this tool versus alternatives like messages_list_chats. Usage context is implied but not thorough.

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