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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds real value beyond that by enumerating the returned substance: a value verdict with margin, redemption thresholds at 10,000/50,000/100,000, each program's great-award line, plus the comparison page and both program pages.

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?

A single sentence that front-loads the headline comparison outcome and then lists the supporting outputs. It is dense but every clause maps to something the caller receives; the only weakness is the unpunctuated run-on style of the closing 'with the comparison page and both program pages'.

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 must convey what comes back, and it does so concretely (verdict, deltas, three redemption tiers, award lines, page links). For a two-parameter read-only comparison tool that is essentially complete; only error/mismatch behavior is left unstated.

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% — both program_a and program_b already document accepting a slug, name, or airline code. The description adds nothing about identifier formats, whether a mixed pair (airline code vs. slug) is allowed, or what happens with an unrecognized program, so it sits at the baseline.

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 states a specific resource and scope: two named rewards programs compared head-to-head on value per point/mile, with a delta ('by how much'). That inherently separates it from single-program siblings like get_points_program or get_point_value, though it never names them.

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?

Usage is only implied by the phrase 'Two rewards programs ... compared' — an agent can infer this is the tool for pairwise comparison. There is no explicit when-to-use vs. when-not, no mention of the single-program alternatives for one-sided lookups, and no stated prerequisite that both programs must exist.

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