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

Beyond the readOnlyHint/idempotentHint annotations, the description discloses key behaviors: 'Zero balances are omitted, so a missing token means balance 0' and explains that SOL in this response is spendable lamports excluding rent-locked amounts. It also details Solana ATA rent and fee requirements, which are materially important for interpreting the balance data.

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 long but every sentence carries operational value, covering purpose, prerequisite, zero-balance semantics, EVM checks, Solana nuances, and fee calculations. It is front-loaded with the core purpose and prerequisite, then organizes chain-specific details in a logical progression.

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 compensates by explaining the return semantics (zero balances omitted, SOL as spendable lamports) and providing concrete thresholds for native drops and ATA rent. It gives an agent everything needed to correctly invoke the tool and interpret its results in the context of the sibling connect_drop operation.

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?

Although schema description coverage is 100%, the description adds essential meaning to the chainId parameter by explaining that 1399811149 means Solana mainnet and that EVM chains use their chain ID. It then connects chainId choice to different balance semantics (EVM gas vs Solana lamports and ATA considerations), going well beyond the schema's one-line description.

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 states a specific verb and resource: 'Get native and token balances for the API key owner Smart Send embedded wallet on a chain.' It also differentiates itself from the sibling tool by explicitly saying 'Always call before connect_drop.' This makes the tool's role unmistakable.

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 gives explicit usage guidance: 'Always call before connect_drop' establishes a prerequisite relationship. It also provides chain-specific rules for EVM and Solana, including what conditions must be checked before a drop, such as gas, token balances, and ATA rent.

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