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

With no annotations, the description carries the full burden and does reasonably well: it discloses the return contents ('unsigned transaction and fee details'), the required local-signing workflow, and per-action credit costs. It omits auth/permission requirements and whether anything is mutated server-side, which keeps it from a 5.

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?

Purpose and the action/credit breakdown are front-loaded and bullet-structured. The credit disclaimer ('indicative only and may change at any time' plus the response-header note) is mildly redundant, costing a point.

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?

No output schema exists, so the description correctly compensates by summarizing return values and the follow-up broadcast step. It covers actions, costs, and workflow, though auth prerequisites remain unstated.

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 genuine meaning to the 'action' enum by explaining what native-coins and spl-tokens each build, beyond the schema's terse 'Action to perform'. The remaining eight parameters get no description-level elaboration.

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 ('Build unsigned Solana transactions ready for signing') and distinguishes itself from sibling prepare_transactions tools for EVM, Kaspa, Tezos, Tron, UTXO and XRP. The action breakdown further clarifies what gets built.

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?

Explicitly routes the agent to the downstream step: 'After preparing, sign locally and broadcast via broadcast_signed_transaction,' naming a real sibling tool. It lacks explicit when-not-to-use guidance (e.g., vs simulate), so it falls short of a 5.

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