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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely new traits beyond that: the call is deterministic, it returns a primary page plus related pages, a quoted reason, a dated tax year, and an optional enquiry, and it explicitly disclaims any legal/tax/eligibility determination.

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 routing behavior and return shape are front-loaded in the first sentence, with the situation list following as supporting detail. The enumeration is long but earns its place given the zero schema coverage; the enum strings are restated alongside their glosses, which is slightly redundant but justified for disambiguation.

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 an output schema present, the description needn't explain return structure, and annotations cover the safety and world-access profile. Combined with a full gloss of every enum value and an explicit scope disclaimer, nothing an agent needs in order to select and call this correctly is missing.

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 0%, so the description carries the full burden — and it does, spelling out all five enum values verbatim alongside a human-readable gloss for each. A caller can map a real-world user utterance onto the correct enum without any further documentation.

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 opens with a specific verb and resource: it "routes a U.S. visitor by situation to The Bitcoin Adviser's U.S. guidance first," which is concrete and identifies the jurisdictional scope. The 'U.S.' qualifier implicitly distinguishes it from siblings like choose_path and choose_retirement_path, though it never names those alternatives 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?

The five listed situations with plain-language glosses ("I'm planning for my family's future," "I have a U.S. retirement account") give a caller clear trigger conditions for selecting each path. The closing boundary statement — no eligibility, legal or tax determination — sets expectations on output. It stops short of saying when NOT to use this tool or which sibling to use for non-U.S. visitors.

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