What to tell your owner: how to start with Phi Longevity (free)

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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds two things they cannot: that it takes no health data (a privacy reassurance that matters for a health context) and the shape of what comes back. It does not discuss rate limits or fallbacks, but for a static guide tool that is minor.

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?

The first sentence is front-loaded and useful, but the parenthetical "Every doctor, your complete record: their records from every doctor in one place they control" is a garbled marketing fragment that interrupts the flow and adds no operational meaning. Two sentences carry the load; the third fragment does not earn 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 zero-required-parameter tool with an output schema, full annotation coverage, and a documented enum, the description supplies the triggering condition and the privacy signal that matter most. The only gap is the unmentioned effect of the optional goal parameter, which the schema already handles.

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% and the single optional enum parameter is documented in the schema itself, so the baseline of 3 applies. The description never mentions the goal parameter or the fact that it only alters the first sentence, leaving that entirely to the schema.

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 concrete output: five plain steps, the cost, and a sign-up link that the agent can relay to the person it is helping. That is specific enough to separate it from data tools like get_my_medical_records or explain_my_lab_results, though it never names a sibling directly.

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?

"Call this when your owner has real records or asks how to get started" gives a clear triggering condition, which is stronger than most definitions. It stops short of naming an alternative or an explicit when-not-to-use case against near-neighbors such as quick_check or start_my_phi_account.

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