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

Annotations cover safety (readOnly, idempotent, non-destructive), and the description goes well beyond them: it explains the two failure modes it catches (unrecoverable mistyped account, silent transfer failure without storage_deposit), plus pricing ($0.02/call over x402 on Base), the prepaid x-credit-token header, the free daily call, and no wallet/API key requirement.

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 decision question and the core mechanic, and most sentences earn their place by carrying behavior or pricing context. It runs long with em-dash asides and the 'Not financial advice' disclaimer, which is marginal 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?

Given an output schema exists, return values need not be spelled out. The description covers purpose, inputs, failure modes, pricing/auth model, and safety profile — nothing an agent needs to invoke it correctly is missing.

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 already 100%, but the description adds real routing semantics: token (+amount) selects a token transfer, while near= is for native-amount sizing. That clarifies the optional parameters beyond their terse schema descriptions.

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 (preflight a NEAR payment to an account) and explicitly frames itself as the NEAR counterpart of agent_pay_gate composing account posture with NEP-141 transfer preflight. The GO/HOLD/STOP outcome model makes the tool's function unmistakable and separable from near_transfer_preflight.

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?

Clear trigger context ('Before you pay a NEAR account') and concrete guidance on which inputs to pass for token vs native transfers. It does not, however, name near_transfer_preflight or agent_pay_gate as alternatives or state when to prefer one over the other.

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