Cost Calculator

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

Annotations declare readOnlyHint=true, so the tool is safe. The description adds that it computes a comparison and highlights the flat pricing model, which is transparent. However, it does not mention error handling or authorization requirements, but given the safety annotations, this is acceptable.

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 (4 sentences), front-loads the main purpose, and follows with usage context and parameter guidance. Every sentence adds necessary information without 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?

With no output schema, the description does not need to explain return values. It covers the main functionality, parameter modes, and comparison details. Missing are possible edge cases or error handling, but for a simple calculator tool it is sufficiently complete.

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 adds value by explaining the difference between subdomain and app_profile, and by listing the enum presets with specific cost for static-site, which is not in 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?

The description clearly states the tool compares deployment costs between Varity and competitors, with a specific verb 'compare' and resource 'cost'. It distinguishes itself from sibling tools (all other tools are for deployment, building, etc.) as the only cost calculator.

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 whenever a developer asks about pricing, cost, hosting bills, traffic costs, or platform comparison.' It also explains the two modes (subdomain for real cost, app_profile for estimate), providing clear context for use.

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