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

Annotations already declare destructiveHint=true and openWorldHint=true, and the description is consistent with a write/external-send operation. It adds real value beyond the annotations: the no-ring delivery semantics, the setup_required failure path with an App Store link, and the threading behavior of session_token. It does not describe rate limits, delivery latency, or whether the send is retractable.

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 short sentences, front-loaded with what the tool does, then setup mechanics, then threading. No filler. Slightly dense but every sentence conveys a distinct, load-bearing fact.

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?

No output schema exists, and the description compensates by naming the setup_required error case and its payload. The remaining gap is the undocumented `from_label` parameter and success-response shape, but for a single-action send tool the coverage is nearly complete.

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 0%, so the description must carry parameter meaning, and it only partially does: it documents `to` (resolved from config.json → user_number) and `session_token` (continue an existing thread). `body` is left implicit and `from_label` is never mentioned, so one of four parameters has no semantics anywhere.

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 pair ('Send a one-way text to the human's phone') and immediately qualifies the channel ('push notification, no ring'). The 'one-way' framing distinguishes it from reply-oriented siblings like wait_for_reply and poll_result without needing their schemas.

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?

Gives actionable operational context: where `to` comes from on a local client, that the hosted server cannot read that file, and that a previous session_token continues the thread. It stops short of explicitly naming an alternative (e.g. 'use call/wait_for_reply when you need an answer'), so exclusions are implied rather than stated.

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