move_message

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

Annotations already indicate readOnlyHint=false, destructiveHint=false, openWorldHint=true, and idempotentHint=true. The description adds crucial context beyond those: it returns {success}, is reversible, executed immediately, audited, and notably explains that on IMAP the message gets a new UID making the old message_id invalid. This goes well beyond what annotations convey.

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 concise: two sentences plus a note. The core purpose is front-loaded, followed by return value and behavioral traits, then the IMAP caveat and the delete alternative. It earns each sentence; only slight redundancy in the note about 'move it back' could be trimmed, but overall it is well-structured.

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?

For a tool with four parameters (two required) and no output schema, the description provides all necessary context: what it does, return shape, side effects (audited, immediate), the IMAP UID caveat that affects message_id usage, and a pointer to delete_message. An agent has everything needed to invoke it correctly.

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 already documents all four parameters. The description does not add substantial new meaning beyond the schema; it mentions the folder_id format and source_folder being IMAP-only, but those are already in the schema. Thus a baseline 3 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 action ('Move a message to another folder of the same account') with a specific verb and resource, and distinguishes it from the sibling delete_message by mentioning that deletion requires approval. This unambiguously differentiates the 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 explicitly tells when to use this tool versus alternatives: it contrasts with delete_message, notes that the operation is immediate without approval, and implies reversibility ('move it back'). It also warns about the IMAP UID change, which guides usage for IMAP accounts. No ambiguity remains.

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