Send a notification to the human's phone

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

No annotations are present, so the description carries the full burden; it discloses the most important trait, that this is non-blocking and does not await a reply. It also signals the interruption semantics ("worth interrupting them for"). It does not mention auth requirements, rate limits, or delivery failure behavior, which are minor gaps for a notification tool but keep this 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?

Three short sentences with zero filler; the purpose is front-loaded and the routing rule to ask_approval is placed last where it matters most. 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?

For a simple notification tool with no output schema and fully described parameters, the description covers purpose, triggering context, and the key non-blocking behavior. Nothing an agent needs in order to call this correctly is missing.

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 title, message, url, and priority are all fully documented in the schema itself, including the quiet-hours semantics of the urgent priority. The description adds no parameter-level detail beyond that, so baseline 3 applies.

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?

"Tell the human something, on their phone" states a specific verb and resource, and the tool is clearly differentiated from its siblings by the explicit contrast with ask_approval. An agent can identify this as a fire-and-forget push notification without opening the schema.

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?

It gives concrete triggering conditions (finishing a long job, a build breaking, anything worth interrupting them for) and an explicit negative case: it does NOT wait for a reply, so use ask_approval when permission is needed. Both when-to-use and when-not-to-use are named.

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