bulk_update_labels

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

Annotations only provide `destructiveHint: false`. The description adds that the tool performs bulk label add/remove and mentions the XOR constraint. However, it does not disclose potential side effects such as rate limits, impact on message state beyond labels, or how conflicts are handled. Given the minimal annotations, the description provides adequate but not comprehensive transparency.

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: the first states the core action, the second adds crucial constraints (namespace and XOR). Every word is essential; no fluff. Front-loaded with the most important information. Excellent structure.

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 7 parameters including nested objects and no output schema, the description covers the essential modes of operation (by email IDs or by match criteria). It explains the XOR constraint and the required folder with match. It does not elaborate on return values or batch processing details (e.g., transactional behavior), but this is acceptable for a bulk operation tool. Missing some completeness, but still strong.

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?

The input schema has 86% description coverage, meaning most parameters already have meaningful descriptions. The description adds value by explaining the XOR relationship between `emailIds` and `match+folder`, and the label namespace convention (e.g., 'Labels/Work'). However, it does not add detailed semantics for each parameter beyond what the schema provides. Baseline is appropriate.

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: 'Add or remove Proton labels on multiple messages simultaneously.' It specifies the namespace ('Labels/IMAP folders under Labels/ namespace') and the XOR constraint between emailIds and match+folder, which distinguishes it from siblings like `update_message_labels` (single message) and `bulk_update_flags` (flags vs labels). The verb 'Add or remove' coupled with 'multiple messages' and 'simultaneously' makes the action and scope unambiguous.

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 explicitly states the XOR condition: 'Accepts emailIds[] OR match+folder (XOR).' This guides the agent on which parameters to use in different scenarios. While it doesn't explicitly mention when not to use this tool (e.g., for single message operations), it provides clear context for the primary usage modes. The guidance is sufficient for most cases.

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