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

With no annotations provided, the description carries the burden of behavioral disclosure. It clearly indicates the tool only constructs and returns instruction JSON rather than executing a transaction, which is a key side-effect-free behavior. The mention of 'client-side TX construction and signing' further signals that no broadcast occurs. It could additionally note that no network call is made, but the current wording is sufficiently transparent.

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 description is a single, efficient sentence that conveys the tool's core function, supported asset types, and return value. There is no redundancy or filler; every word contributes to understanding the tool's behavior and output.

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?

The description is sufficiently complete for a tool of this simplicity. It covers the operation (building a transfer instruction), the asset types (SOL and SPL), and the output format (JSON with programId, keys, data), which aligns with the existence of an output schema. An agent can confidently select and invoke the tool based on this description and the 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 input schema already provides complete descriptions for all four parameters (100% coverage), including the distinction between native SOL and SPL token transfers and atomic units. The description adds no additional parameter-level details beyond the schema, so it appropriately meets the baseline without further compensation.

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 uses the specific verb 'Build' and identifies the resource as 'a SOL or SPL token transfer instruction', making its function unambiguous. It also distinguishes itself from related siblings like solana_sendTransaction by clarifying it returns instruction JSON for client-side construction and signing, not broadcasting the transaction.

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 implies its use case: building an instruction as a precursor to sending, explicitly stating it is for 'client-side TX construction and signing'. It does not explicitly name alternatives or when not to use it, but the sibling context (e.g., solana_sendTransaction for sending) makes the intended workflow clear enough for an agent.

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