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

Annotations indicate read-only, and the description adds context by explaining the computation and benchmark comparison. It does not contradict annotations and provides additional behavioral insight.

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, front-loaded with key outputs and benchmarks, followed by computation explanation. No fluff or redundancy.

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?

Lacks details on output format (e.g., numeric values, comparison text), but covers key deliverables and all parameters. Adequate for a read-only calculator with full schema.

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?

Input schema has 100% coverage with descriptions. The tool description adds value by explaining how parameters relate (e.g., LTV from ARPU, gross margin, churn; CAC for ratio), though the schema already covers basics.

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 computes LTV, LTV:CAC ratio, and CAC payback, using ARPU, gross margin, churn, and CAC. It distinguishes itself from siblings as the only unit economics tool among many financial calculators.

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 implies use for SaaS/subscription businesses by mentioning standard benchmarks, but it does not explicitly state when to use this tool over siblings like roi or break_even, nor does it provide exclusion criteria.

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