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

Annotations declare readOnlyHint=true and openWorldHint=false, so safety is already established. The description adds that no sign-in is needed, which is useful context, but doesn't describe the computation or output format. The 'ask the user' instruction is behavioral guidance but not deep transparency.

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?

Three sentences, front-loaded with the main purpose, then the sign-in note, then the user-input instruction. No wasted words, though the last sentence could be more tightly integrated.

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 read-only estimation tool with no output schema and full parameter documentation, the description is nearly complete. It could mention what the output looks like or how the cost is calculated, but it covers the essentials.

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 schema fully documents all four parameters with defaults and constraints. The description reinforces the required inputs and the default-assumption nature, adding slight value beyond the schema.

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 (estimate) and resource (revenue lost to unanswered calls), and names the exact inputs (call volume, average job value). This distinguishes it clearly from siblings like ringguard_cost_estimate and my_stats.

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?

Implies usage ('Ask the user for their numbers rather than guessing them') but doesn't explicitly say when this tool should be used vs alternatives like ringguard_cost_estimate. No exclusions or prerequisites are stated.

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