inbox_ack

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

With no annotations, the description carries the burden and does disclose two real traits: it emits a message.read receipt to each sender (a visible side effect) and returns a specific result shape. It stops short of permissions, rate limits, or what happens to unacknowledged messages.

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, no filler, purpose and return shape and side effect front-loaded in that order. Every sentence earns its place.

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?

An output schema exists, so return values need not be spelled out, yet the description still names the response keys. Auth and idempotency are covered by a rich schema. The main gap is the absence of when-to-use routing among the inbox_* siblings.

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 agent_id, session_id, message_ids and session_secret are fully documented in the schema, including idempotency and trust-mode requirements. The description adds nothing about parameters, so baseline 3 is correct.

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+resource: acknowledge messages into history, with a parenthetical clarifying it counts as a read. This is clear enough to distinguish it from inbox_pull/inbox_peek, but it never names those siblings or explains how ack differs from them.

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?

No guidance on when to acknowledge versus pulling, peeking, or reading history. The idempotency note lives in the schema, not the description, and there is no mention of prerequisites or when-not-to-use.

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