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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description adds genuinely non-obvious behavior: dual-router routing with Chord-first fallback, the 2-minute quoteId expiry, and that supplying a taker changes the response to include a transaction plus simulation. These are behaviors an agent cannot recover from the schema.

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?

Three dense sentences, front-loaded with the core purpose, then routing behavior, then unit/ID semantics. Nearly every clause carries information; the opening superlative ('Best swap quote') is the only mild marketing filler.

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 the work of describing the return (a quoteId valid for 2 minutes, and optionally a transaction plus simulation when taker is provided). Solana's REST-only path is documented in the schema but not in the description, which is a minor gap for an EVM-focused tool.

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 coverage is 100%, so the baseline is 3, but the description adds meaning the schema does not: the zero address maps to the native asset, and the taker parameter upgrades the response to include a transaction and simulation. Amount unit semantics are repeated from the schema rather than extended.

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+resource ('swap quote') with scope ('on an EVM chain') and an implicit contrast to the execution sibling by promising a quoteId rather than a transaction. It never names chord_swap_tx or another sibling explicitly, so differentiation is inferable rather than stated.

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 description explains routing priority (Chord's router first, another aggregator as fallback), which is useful operational context, but it gives no explicit when-to-use guidance relative to siblings like chord_swap_tx or chord_ask. The 2-minute quoteId lifetime implies a follow-up execution step but that is left for the agent to infer.

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