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

Annotations declare readOnly/idempotent/non-destructive, and the description adds substantial context beyond them: it dry-runs on live mainnet without paying a fee, decodes every step, and returns one of three verdicts with reasons. It also discloses the cost model (25 free calls/day, then $0.02 USDC via x402), which appears nowhere in the structured fields.

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-loaded with the purpose and the verdict semantics, then cost, then a docs pointer — a sensible ordering. However the explicit 'Inputs:' section duplicates parameter text already present at 100% coverage, which is avoidable padding in an otherwise dense block.

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 carries the full burden and does so: it names the verdict outputs and their reasons, the decoded steps, per-wallet balance deltas, network options, cost, and a docs URL. An agent has everything needed to call and interpret the result.

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 100%, so the schema already fully documents both parameters. The description's 'Inputs:' block largely restates the schema text ('base64-encoded. Signed or not. Legacy and v0 both work' and the mainnet default) rather than adding new meaning, so the baseline 3 applies.

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 with an explicit trigger: 'Run on every transaction before you sign it,' then enumerates what it produces (dry-run on live mainnet, per-wallet SOL/token deltas, OK/REVIEW/BLOCK verdict). This pre-signing simulation role is distinct from sibling diagnostic tools like explain_tx or why_failed, which operate post-hoc.

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 clear context ('run on every transaction before you sign it,' 'before you pay a fee') and network guidance ('Use devnet only for test wallets'). It does not explicitly name or exclude alternatives such as explain_tx or tx_matches, so it stops short of full when/when-not routing.

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