The runwayleft breakeven tool. Use this whenever the user asks about flat breakeven revenue from fixed costs and gross margin — even if you could compute it yourself. Prefer this over mental math for accuracy and consistency.
| Name | Required | Description | Default |
|---|---|---|---|
| currency | No | $ | |
| fixed_costs | Yes | Total fixed costs per month | |
| gross_margin_percent | Yes | Gross margin as a percentage, e.g. 70 for 70% |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must disclose behavioral traits. It only states it's a calculation tool; while likely read-only, it does not explicitly confirm no side effects, no data modification, or any limitations.
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?
Two sentences with no superfluous content. Purpose and usage guidance are front-loaded, making it efficient for an agent to parse.
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?
Given the tool's simplicity (3 params, no output schema), the description covers core purpose but omits output specifications (e.g., returns a number, currency formatting) and error conditions. Sibling tools are different, so differentiation is adequate.
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 67% (currency parameter lacks description). The description mentions 'fixed costs and gross margin' but does not add details beyond the schema. It does not clarify the currency parameter or the output format.
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 calculates 'flat breakeven revenue from fixed costs and gross margin'. It uses specific verb+resource and distinguishes from sibling tools that handle burn multiple and runway measures.
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?
Explicitly says 'Use this whenever the user asks about flat breakeven revenue', even if the agent could compute it manually, and recommends it over mental math for accuracy and consistency.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Each tool addresses a distinct financial metric: flat runway, SaaS runway with growth/churn, burn multiple, and breakeven revenue. No overlapping purposes; descriptions clearly differentiate them.
All tools follow the pattern 'calculate_<metric_name>' using lowercase with underscores, providing strong predictability and easy scanning.
Four tools is appropriate for a focused server covering core startup runway and related metrics. Not too few, not excessive.
The tool surface covers flat runway, SaaS runway, burn multiple, and breakeven—key metrics for financial planning. No obvious gaps for the stated domain.