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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions Monte Carlo simulation and returns a probability, but it does not clarify whether the output is the target amount, the probability, or both, nor does it disclose assumptions, determinism, or limitations. This ambiguity is significant for a tool with no output schema.

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 description is concise and front-loaded, with two sentences that directly state the purpose and method. No wasted words or redundant details.

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 tool with 8 parameters and no output schema, this description is incomplete. It does not explain the output format, the role of inputs like current_savings or portfolio_volatility, or the simulation's assumptions. The tool's complexity demands more context than 'runs Monte Carlo and returns probability' provides.

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?

The description adds no parameter-level semantics beyond the schema. Several parameters (inflation_rate, apply_inflation) lack full descriptions in the schema, and the description does not compensate or explain how parameters relate to the simulation. With 63% schema coverage, the description should provide additional context but does not.

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?

The description clearly states the tool's function with a specific verb ('Estimate') and resource ('savings target needed for Financial Independence / Early Retirement'), and further distinguishes it by mentioning Monte Carlo simulation and probability of survival. This differentiates it from sibling tools like calculate_coast_fire, which likely focuses on a different FIRE metric.

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 description provides clear context for when to use this tool: when estimating a FIRE savings target with probabilistic simulation. However, it does not explicitly state when not to use it or mention alternative sibling tools, so it stops short of a full 5.

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