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

The description frames the tool as a read-only estimation ('Estimate', 'Answers'), matching readOnlyHint, but the annotations also set destructiveHint: true. The description does not disclose any destructive behavior, and 'estimate' directly conflicts with the destructive hint, so the agent receives contradictory signals.

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 front-loaded with purpose, followed by examples and operational rules. It is moderately sized and each sentence adds information, though the example questions are slightly redundant with the initial purpose statement.

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 7-parameter calculator with no output schema, the description explains the return values (points plus great-circle distance), the program-specific calculation basis, and required program slugs. It does not describe the exact response shape or error conditions, but it is sufficient for selection and invocation.

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 baseline is 3. The description adds real cross-parameter meaning: fare_price is only needed for revenue-based BA/AA earnings, while Flying Blue XP is segment- and cabin-based, clarifying when to supply fare_price and how segments factor in.

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 uses a specific verb ('Estimate') with a precise resource (elite-qualifying points plus great-circle distance), names the three supported programs, and gives concrete example questions. This clearly distinguishes it from siblings like get_points_valuation or get_earning_rates.

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 example questions ('how many tier points is LHR–JFK in business?') and program-specific earning rules imply when the tool should be used. However, it does not explicitly say when to prefer it over alternatives such as get_earning_rates or when not to use it.

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