Find a thread

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

Annotations already declare readOnlyHint=true, so the read-only nature is covered. The description adds valuable behavioral context: it searches across All Mail, groups messages by conversation, and highlights which ones carry documents. This explains the thread-reassembly behavior beyond the 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?

Two sentences, each earning its place. The first sentence is a crisp summary of the action, and the second provides essential background and a usage directive. There is no fluff or redundancy.

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 and the absence of an output schema, the description adequately conveys what the tool returns (all conversation messages with document flags). It could mention ordering or pagination, but the core scope and behavior are sufficiently covered for a read-only thread pull.

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%, and each parameter already has a clear description (e.g., 'uid' is 'A message in the thread (its subject is used)'). The tool description adds no further parameter semantics beyond what the schema provides, so the baseline of 3 applies.

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 uses the specific verb 'Pull' and clearly states the resource: every message of a conversation from All Mail. It also distinguishes the tool from siblings by mentioning document-carrying messages and the IMAP/UI mismatch, which is unique to this thread-finding tool.

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 gives explicit context: run this before concluding what a thread needs, and explains the critical IMAP vs Proton UI distinction that makes this necessary. It doesn't name alternative tools for when not to use it, but the guidance is strong enough to signal when this tool is the right choice.

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