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

Annotations already declare readOnlyHint=false, destructiveHint=false, idempotentHint=true, so the safety profile is partly covered. The description adds genuinely new context by explicitly reassuring that 'Nothing is deleted and no email is sent' and by disclosing the side effect on list_inbox results, which the annotations cannot express.

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?

Three short sentences, front-loaded with the primary action and effect, followed by the safety reassurance and the usage trigger. Every sentence carries distinct information with 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 simple two-parameter, non-destructive toggle with no output schema and full annotation coverage. The description covers action, effect on sibling output, safety, and usage timing, leaving nothing an agent needs 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 description coverage is 100%: both parameters are documented in the schema, including the archived default and the source of conversationId. The description's 'or brings it back' only loosely gestures at the boolean toggle, adding little beyond the schema, so the baseline 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 ('files a conversation away', 'brings it back') and names the observable effect on the sibling tool list_inbox. An agent can distinguish this from get_thread, list_inbox, or redirect_thread without opening any schema.

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?

Gives explicit timing guidance: 'Use it once a thread is dealt with, so the inbox reflects what still needs attention.' This is clear context for when to invoke, but it never names a competing alternative (e.g. redirect_thread, discard_draft) or states when not to use it.

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