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

Annotations already cover safety (readOnly, idempotent, non-destructive), yet the description adds genuine behavioral context: the fixed/local burn split, city-level vs national scaling, Factbook-only country fallback, and the 'purchasing-power estimate, not financial advice' caveat. That is meaningful added transparency beyond the structured fields.

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-loaded with the audience and the core computation, then the methodology, then the return summary and caveat. Dense but every clause carries information; slightly long, though nothing is truly wasted.

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 an output schema present, the description need not enumerate return fields, and its inclusion of them is harmless but slightly redundant. For a 7-param analytical tool it supplies adequate scope, methodology, and caveats; only explicit alternative-tool guidance is missing.

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 100%, so the baseline is 3; the description earns an extra point by explaining the conceptual model behind `fixed` (location-independent slice that won't fall) and the cost-of-living ratio logic applied to `targets`, adding interpretive meaning beyond the field text.

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 ('computes how many extra months of runway relocating... buys') with the resource and scope, and even names the audience (founders/freelancers). An agent can distinguish it from siblings like find_fire_locations or retire_on_budget 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?

The framing 'For founders/freelancers stretching savings' clearly signals the use case and implicitly excludes retirement/visa-planning tools. It does not, however, name an alternative or state when NOT to use it (e.g., vs. find_fire_locations), so it stops short of explicit routing.

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