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

With readOnlyHint/openWorldHint given, the description still adds substantial behavior: the hard eligibility gates applied before scoring, the configurable scoring dimensions, what the recommendation returns (reasons, alternatives, data used, missing information, freshness), and the fallback case of no reliable recommendation. It also discloses the trust model (LIVE/INDICATIVE/HISTORICAL/ESTIMATED, estimated savings never realised) and the free-allowance cost. The POST endpoint mention is a mild tension with readOnlyHint, but the artifact is an advisory analysis, not a business-state mutation.

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 purpose is front-loaded in the first clause and nearly every subsequent sentence carries real information (eligibility order, output contents, confidence labels, cost). It is a dense semicolon-chained paragraph, though, and the line about "the same service for every payment-intelligence tool" is more puzzling than illuminating.

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 15-parameter tool with nested objects and no output schema, the description covers the decision logic and describes the return payload in enough detail (reasons, alternatives, data used, missing info, freshness). Only minor gaps remain, such as how the analysis_id read path relates to a fresh analysis.

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 schema already documents all 15 parameters, including the weights object and the enum. The description only restates the scoring dimensions and eligibility logic at a high level, adding little syntax or meaning beyond the schema. A baseline of 3 is appropriate.

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?

"Selects a route for one payment, with the reasons" gives a specific verb (selects), a resource (route), and the scope (one payment). It clearly differentiates from a quote ("Not a firm quote"). However, it never names its nearest siblings (assess_route, price_routes, compare_payment_providers, swapeazi_route_compare), so differentiation from those is left implicit.

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?

It gives useful context that this is pre-approval analysis rather than a firm quote and that the user must confirm with the provider. It also signals the free-tier allowance. But there is no explicit when-to-use/when-not guidance relative to the many overlapping route tools, so an agent must infer which tool to pick.

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