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

readOnlyHint=true and openWorldHint=false already establish the safety profile, so the description is not carrying that burden. It adds real value by disclosing that results are unfiltered ('every route') and include a live availability flag, but says nothing about result size, ordering, or whether availability is a snapshot.

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?

One sentence, front-loaded with the resource and its scope, with no filler. The parenthetical '(from/to slugs)' is slightly compressed and takes a beat to parse, but nothing is wasted.

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 no-argument, read-only list tool with no output schema, the description covers what comes back and the key availability signal. Minor gap: 'whether both sides are available' leaves the exact shape of the availability fields ambiguous without an output schema.

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?

The tool takes zero parameters, which is the baseline-4 case; there is no schema semantics for the description to supplement. The mention of from/to slugs correctly signals these are output fields rather than inputs.

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 states a specific verb-and-resource pair ('every route') and names the payload fields it returns (from/to slugs, availability). It does not distinguish itself from siblings such as list_assets or get_quote, so it stops short of a 5.

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?

Usage is only implied: the mention of slugs and 'available right now' hints that this is the discovery step before quote/swap calls, but no when-to-use, when-not-to-use, or alternative tool is named. An agent must infer the routing from sibling names alone.

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