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

Annotations already establish readOnly, idempotent, non-destructive, and closed-world behavior, so the safety profile is covered. The description adds genuinely new behavioral context: results come from a researched transfer-partner table with an as_of date, ratios fluctuate, and transfer bonuses are excluded — a caveat that materially affects how an agent should present results.

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 short sentences with the outcome statement front-loaded, followed by the data-provenance caveat and the input instruction. Every sentence carries information and nothing is padded.

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 still conveys what the response contains (eligible conversions, ratios, post-transfer totals). It omits details like response shape or handling of unknown programs, but the freshness disclaimer covers the riskiest ambiguity for a 3-required-parameter 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 description coverage is 100%, so the schema already documents balances, target_programs, and miles_needed with enums and example slugs. The description only echoes the balances requirement and adds no format, edge-case, or semantics beyond what the schema already states, so the baseline 3 applies.

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 gives a specific computed outcome: which bank points convert into a target program, at what ratio, and the resulting balance. That is far more precise than the title 'Transfer options' and is clearly distinct from valuation (points_value) or award pricing (award_chart), though no sibling is named explicitly.

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?

'Pass the traveler's balances' tells the agent the required input, and the tool's scope is implied by its phrasing, but there is no explicit when-to-use/when-not guidance and no routing to the sibling tools. Usage is inferable rather than stated.

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