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

Goes well beyond the annotations (destructiveHint/openWorldHint/non-idempotent) by disclosing the concrete side effect: an immediate consent verification call is placed and reminders are delivered only after acceptance. It also warns that a typo results in a real call to a stranger, which is critical behavioral context for an outbound-calling mutation.

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?

Front-loads the purpose, then safety warnings, then a clean Args block. Slightly verbose with illustrative asides (e.g. 'an elderly parent', 'Mother'), but each sentence contributes meaning rather than restating the schema.

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 destructive, outbound-calling mutation with an output schema present, the description covers purpose, side effects, consent flow, and every parameter's semantics. An agent has everything needed to call it correctly and safely.

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 carries the full burden, and it does: it documents all three params, explains that name is used in the call greeting, mandates full E.164 format with a concrete example for phone, and clarifies relationship is an optional user-facing label.

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 and resource ('Add another person who can receive reminder calls') and the domain concept (recipient of reminder calls). It is clearly separable from siblings like remove_recipient, list_recipients, and resend_recipient_verification.

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 a clear usage context (adding a new recipient) plus important preconditions — only add someone the user has permission to call, and confirm the number digit by digit. It does not explicitly route to siblings such as resend_recipient_verification for already-added people, so it stops short of a 5.

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