send_sms

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

Annotations declare destructiveHint and openWorldHint, but the description adds the crucial behavioral gate that this must not be invoked without explicit user approval of the exact recipients and text, plus the fact that multiple numbers fan out to a group message. It does not cover delivery/rate-limit behavior, but the approval requirement is the highest-value disclosure here.

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 lines with zero padding; the action and the approval precondition are front-loaded before the contact-resolution hint. 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 no explanation, and annotations already cover the safety profile. The description supplies the missing operational constraints (approval gate, group semantics, name resolution) needed to invoke this destructive, open-world tool correctly.

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 0%, so the description must carry parameter meaning; it explains that 'to' holds phone numbers (not names) and that multiple values produce a group message, which is real semantics beyond the bare array-of-strings schema. 'text' is left implicit, though its name and string type make it self-evident.

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 (send) and resource (SMS) plus the originating identity (user's phone and number), and clarifies the multi-recipient case as a group message. It also names find_contact, letting an agent distinguish this from the contact-resolution tools without opening a 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?

Gives an explicit precondition ('ONLY call after the user has explicitly approved this exact recipient list and text') and routes a prerequisite sub-task to the alternative tool ('resolve names with find_contact first'). When-to-use and which-sibling-to-use are both covered.

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