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

Annotations already declare readOnly, idempotent and non-destructive, so the description's extra context is what earns credit: deterministic primary route plus fallbacks and a proof digest on return, and the assurance that it is advisory only — it does not move caller traffic or take a fee. That is genuinely useful behavioral disclosure beyond the structured hints.

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?

Two tight sentences, front-loaded with the verb and resource, then the read-only contract. The closing 'does not collect a hidden fee' clause is slightly defensive framing but still conveys a real behavioral guarantee.

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 does sketch the return (primary route, fallbacks, proof digest), which is helpful. However, for a tool whose only real complexity is the nested routes array, leaving the item fields and transaction_value_atomic undocumented is a meaningful gap.

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 must compensate and largely does not. It never mentions transaction_value_atomic, and only indirectly hints that samples_ms feeds the p95 and that error_rate/available drive 'health'; nested item fields (id, endpoint, maxItems 64, 256 samples) go unexplained.

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: rank caller-supplied HTTPS routes by measured p95 latency and health. That is far more specific than the sibling tools, which operate in an unrelated 'omnidome' domain, though the phrase 'through PANGI' adds a proper noun without explaining the mechanism.

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 'caller-supplied' framing implies you must already possess candidate routes, but there is no explicit when-to-use, when-not, or comparison to an alternative. Usage must be inferred from the input shape rather than stated.

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