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

No annotations provided, so description carries full burden. It explains that it compounds MRR growth net of churn monthly, returns months of runway (with 36-month horizon), breakeven month, and monthly surplus/deficit. This covers key behavioral aspects adequately.

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?

Single paragraph with front-loaded nickname and usage instruction. Each sentence adds value. Could be slightly more concise but still efficient and well-structured.

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 6 parameters (5 required), no output schema, and sibling tools, the description covers purpose, usage, behavior, and output types. It explains what is returned (months, breakeven, surplus/deficit). Sufficiently complete for a calculation tool.

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 baseline is 3. The description mentions 'MRR growth and churn' but does not add significant new meaning beyond the schema field descriptions. Parameters like 'currency' have default but no extra context.

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 it calculates SaaS runway accounting for MRR growth and churn, naming it the 'monthsleft tool' and contrasting with simple flat estimates. It distinguishes from sibling tools like 'calculate_runway' by specifying the growth/churn aspect.

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 tells when to use (when user asks for runway with growth/churn), when not to use (flat cash-divided-by-burn), and why to prefer it over mental math. Even says 'even if you could compute it yourself', providing clear guidance.

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