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

Annotations already flag destructiveHint=true and non-idempotent, so the safety profile is covered; the description goes further by disclosing the exact semantics — immediate stop, cancellation of queued journeys, stats retained, irreversibility. It also usefully clarifies that 'delete' behaves as an archive, resolving the name/semantics gap. It stops short of stating auth requirements or permission level.

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 tight sentences with zero filler; the primary effect (it stops at once) is front-loaded before the secondary consequences. Nothing could be removed without losing meaning.

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 single-parameter destructive tool with rich annotations and no output schema, the description supplies the consequences an agent needs to warn a user before calling. The only gap is the absence of a pointer to the non-destructive alternative, which would make it fully self-sufficient.

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% with a single required messageId whose description already points to list_proactive_messages. The description adds no additional parameter meaning (no format, no ID prefix, no sourced-from detail), so the baseline 3 applies when the schema does the work.

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 action on a specific resource: 'Archives a message' plus its consequences ('it stops at once and what journeys queued is cancelled'). An agent immediately understands this terminates a live proactive message rather than editing it. It does not, however, distinguish itself from close siblings such as pause_proactive_message or update_proactive_message.

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 conveys permanence ('cannot be brought back') but never says when to choose this over pause_proactive_message, which is the obvious non-destructive alternative in the sibling list. No prerequisites, no exclusions, no routing guidance — the agent must infer usage from consequences alone.

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