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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the description's added value is the pricing and auth behavior: a free tier with a daily per-caller quota, and the instruction that payment headers (X-Payment, X-Payment-Tx, Bearer fg_…) go in the MCP request headers, not the parameters. That is genuinely useful context beyond the annotations, though it says nothing about rate-limit exhaustion or failure behavior.

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 core pitch is well front-loaded, but the same information is then repeated twice more in the [zh] and [en] vendor-asset lines and again in the arg list. Redundant bilingual restatement adds length without adding meaning.

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 and no required parameters, the description does supply the return fields, quota model, and auth-header placement, which covers most of what an agent needs. The missing piece is parameter meaning, which is entirely absent for a 0%-coverage 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?

Schema description coverage is 0% across four parameters, so the description must carry the semantic load. It only restates the parameter names (token, amount, from_chain, to) and notes they are optional; it never explains formats, chain naming conventions, or what `to` designates, leaving the schema gap unaddressed.

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 first sentence gives a concrete verb-plus-resource framing ("Ask 'what is the cheapest bridge route'") and enumerates the returned fields: deepest route, fee percent, ETA, amount received. It does not, however, distinguish this tool from the close sibling bridge-quote.quote_compare, so an agent cannot tell from the text alone which quote tool to pick.

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 by the quoted user question ("what is the cheapest bridge route") and by the free-tier framing. There is no explicit statement of when to prefer this over quote_compare or bridge-flow.bridge_now, and no stated preconditions or exclusions.

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