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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, yet the description adds real behavioral context on top: the dimensions returned (onboarding, category tolerance, account stability, reserves, paperwork, pricing approach, disputes), the qualitative (non-numeric) nature of the output, an explicit "not financial advice" disclaimer, and a data-handling constraint against sending card numbers, government IDs, or bank details.

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?

Front-loaded with the trigger condition, then output nature, then limits and safety — a sensible ordering. It is a fairly dense paragraph, but each clause (what it returns, what it omits, what not to send) carries distinct information rather than padding.

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 three-required-param, closed-world advisory tool with an output schema, the description covers everything an agent needs: when to invoke, what the comparison covers, what it deliberately will not provide, and the PII restriction. The explicit disclaimer about missing fee numbers and approval odds is exactly the gap an agent would otherwise misrepresent to a merchant.

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% and the enum values for current_processor and situation are self-documenting, so the schema carries the parameter burden. The description only restates the three inputs generically ("the current processor, the niche, and the current situation") without adding format or edge-case meaning, so 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?

States a specific verb+resource (compare processor fit) and defines the exact comparison: staying with a named current processor such as Stripe/PayPal/Shopify Payments/Square versus moving to a high-risk merchant account. That framing is clearly distinct from siblings like match_merchant_account or check_policy_readiness, which imply a single-answer or single-dimension output rather than a side-by-side.

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?

"Use when a merchant asks whether to stay with their current processor ... or move to a high-risk merchant account" is an explicit trigger condition, and the description bounds scope by ruling out fee numbers, approval odds, and financial advice. It stops short of naming a sibling tool as the alternative for those excluded needs, so routing for adjacent intents is left to inference.

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