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

Annotations already declare this is a non-destructive, non-idempotent write. The description adds genuinely new behavior that annotations cannot carry: the comment is visible to everyone who can open the alarm and the alarm's creator is notified. It does not address auth requirements or failure modes, so it falls short of a 5.

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?

Four compact sentences with the action and target front-loaded, and no repetition of the title. The fragment 'For words; a heart is separate' is slightly telegraphic, which costs a point on structure but not on length.

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 no output schema, the description still covers purpose, audience, notification side effect, character limit, and the sibling alternative, which is most of what an agent needs to call it. Missing only permission/auth expectations and confirmation of what a successful call returns.

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 both parameters are already documented in structured data; the description's 'from its link or code' merely echoes the schema's link/comment definitions. The 280-character limit is reinforced but already enforced by the schema's maxLength. Baseline 3 is appropriate when the schema does the heavy lifting.

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 (posts) and resource (comment) scoped to an alarm the person rides or made, retrieved via its link or code. It also explicitly separates itself from a sibling: 'For words; a heart is separate' distinguishes it from heart_alarm, and the read/write contrast distinguishes it from read_comments.

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?

'For words; a heart is separate' routes the agent to heart_alarm for reactions, and 'an alarm the person rides or made' gives the eligibility condition. It stops short of stating when-not to use it or naming the alternative tool verbatim, but the context is clear enough to act on.

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