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

Annotations already declare this is a non-read-only, non-destructive write, and the description adds that the effect is visible to collaborators. It says nothing about whether the status persists, auto-clears after inactivity, or how it interacts with the heartbeat tool, which is the main behavioral question an agent would have.

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?

A single short sentence that front-loads the effect and explains both states in one clause. Nothing is padded or redundant.

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?

With an output schema present, return values need no explanation, and the description is adequate for a one-required-param status setter. The gaps are the undocumented note parameter and the absence of any pointer to heartbeat/presence_heartbeat as alternatives.

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 33%; the description usefully glosses the enum values as 'working (active)' and 'waiting (idle)', which adds meaning beyond a bare enum list, and idempotency_key is well documented in the schema itself. The 'note' parameter is never mentioned anywhere, so part of the remaining coverage gap goes unaddressed.

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?

The description gives a clear verb ('tell') and states the effect on collaborators plus what the two states mean, so an agent knows this sets its own availability. It does not distinguish itself from near-siblings such as presence_heartbeat or heartbeat, which also concern agent liveness.

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 by the active/idle framing — call it when your work state changes — but there is no explicit guidance on when to prefer this over heartbeat or presence_heartbeat, nor on whether idle status expires on its own.

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