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

Annotations already flag destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds genuine context beyond that: the delete semantics ('through – that message and every older one') and the pro/upgraded-inbox prerequisite, which materially affects the blast radius of a call.

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 dense sentences with no filler; the action-to-parameter mapping is front-loaded and each clause carries required information.

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 destructive, 5-parameter tool with no output schema, the description covers both actions, their required inputs, and the pro prerequisite. It does not address auth (passport_token) or error/partial-failure behavior, which are minor gaps given annotations carry the safety hints.

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 the baseline is 3, but the description adds a constraint the schema does not make explicit: ack accepts either ids or through, while delete accepts only through. That routing rule is the single most important thing an agent needs before calling.

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 pair (acknowledge/delete) and resource (messages in an upgraded webhook inbox), plus the bulk scope ('many messages at once'). It implicitly distinguishes itself from single-message siblings like inbox_messages, but never names an alternative explicitly.

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?

Usage is implied: it is the bulk path for an upgraded (pro) inbox. There is no explicit 'use this when…' or routing to inbox_messages/inbox_pro_get for single-message reads, so the agent must infer the boundary.

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