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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), but the description adds real context beyond them: the default retirement age of 65, how saving is inferred, the low/mid/high + confidence return shape, a 'not financial advice' caveat, and a non-error empty-state contract pointing to message and next_step_url. That empty-state handling is a meaningful behavioral disclosure an agent would otherwise get wrong.

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 sentences, none wasted, with the purpose front-loaded and the operational empty-state rule placed last as the actionable caveat. Dense but appropriately sized for a tool with a nested-parameter schema and no output 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?

With no output schema, the description usefully summarizes the return shape and the empty-result contract, and no annotations are contradicted. The remaining gap is parameter documentation, particularly the growth_rates object and the month key, which an agent would have to guess at.

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% for four parameters, so the description must compensate. It partially does: retirement_age's default (65) and monthly_saving's history-inferred nature are explained, but 'month' and the low/mid/high growth_rates object are left entirely undocumented in both places, leaving two parameters opaque.

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 ('projects the user's net worth at retirement age') plus the computation basis (future-value maths, history-inferred saving), which cleanly separates it from siblings like get_net_worth and simulate_scenario. An agent can identify the tool 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?

Implied usage is clear (retirement-age net worth projection) and the empty-result branch gives concrete operational guidance, but the description never says when to prefer this over simulate_scenario or get_net_worth. No explicit alternatives or exclusions are named.

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