imap_find_thread_messages

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

No annotations are provided, so the description carries the full burden. It discloses the underlying mechanism (RFC 3501 HEADER search on In-Reply-To and References) and asserts broad server compatibility. It does not cover authorization needs or return format, but the technical detail adds substantial value.

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 with no wasted words. First sentence states the core operation, second sentence adds a use case and technical context. Every sentence earns its place.

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 explains the purpose and mechanism well, but with no output schema, it omits what the tool returns (e.g., list of message IDs or something). This gap reduces completeness for an agent that needs to interpret results.

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 baseline is 3. The description adds value by explaining the relationship between searchFolder and sourceFolder (thread-based correspondence), which is not obvious from individual parameter descriptions. However, it does not elaborate on each parameter individually beyond the schema.

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 finds messages in searchFolder that belong to conversation threads of messages in sourceFolder. It uses specific verbs and resources, and the unique thread-finding purpose distinguishes it from sibling tools like imap_search_emails.

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 a clear use case ('catching replies that arrived after a thread was sorted') and mentions it works on any IMAP server. However, it does not explicitly state when not to use it or name alternatives among siblings.

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