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

Adds substantial context beyond the annotations: nothing is permanently deleted or expunged, the message receives a new id in Trash, and on Gmail it leaves every label including All Mail. The new-id disclosure is operationally critical and appears nowhere in the annotations or schema.

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?

Front-loaded with the core semantic (soft delete), then each following sentence adds a distinct fact: recoverability, id source, id change, no-op case, Gmail behavior. No filler.

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?

A mutation tool with annotations covering safety and idempotency, an output schema covering returns, and a description that closes the remaining gaps (recoverability, id mutation, provider-specific side effect). Nothing needed to call it correctly is missing.

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%, so both parameters are already documented, and the description only restates that message_id comes from search_messages. It does add the post-condition that the id changes in Trash, but that is an outcome rather than parameter meaning, 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?

States a specific verb and resource plus the exact semantics: 'move it to the Trash folder, where it can still be recovered.' This clearly separates it from a hard-delete or from move_message, which relocates to arbitrary folders.

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?

Tells the agent where the id comes from ('from search_messages') and covers the no-op case ('A message already in Trash is left as it is'). It doesn't explicitly name move_message as the alternative for non-Trash relocation, so routing between the two is implied rather than stated.

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