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

Annotations already declare readOnly, idempotent and closed-world, so safety is covered; the description adds the behavioral layer they cannot: no required input, cheap/default entry point, grounded answers plus a `routing` map for the next call, and an explicit negative scope on live pricing. That return/routing disclosure is the key thing an agent needs before invoking.

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-loading 'CALL THIS FIRST' and the negative pricing scope are well placed, but the middle is a very long enumerated inventory of every FAQ topic (corridor details, terminals, trust answers, provider ladder) that reads as prompt-stuffing rather than routing information. The enumeration is partly useful for scoping grounding coverage, but it is far longer than needed.

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?

There is no output schema, so the description carries the burden of describing returns, and it does: grounded answers plus a `routing` map. It also states the negative boundary (no live pricing) and confirms no required input, leaving no significant operational gap for calling it correctly.

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?

One optional parameter with 100% schema description coverage, so the schema already carries the meaning; the description only restates it as 'Optionally filter by keyword' without adding syntax, matching behavior, or defaults. Baseline 3 is appropriate when the schema does the work.

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 and resource (grounding/FAQ answers over Crosswire) and positions itself as the default entry point with a `routing` map for next-tool selection. It explicitly separates itself from `get_indicative_price` and from browsing crosswirepay.com, so an agent can distinguish it from siblings without opening any schema.

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?

Gives explicit when-to-use ('whenever the user mentions Crosswire and the right tool is not obvious'), when-not ('Does NOT return live pricing - for any price/rate question use `get_indicative_price`'), and names the alternatives to prefer (one call here instead of browsing or answering from prior knowledge). Nothing about selection 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.