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

With no annotations, the description carries the full burden and does well: declares read-only behavior, zero cost and no quota/balance consumption, and the 401 failure mode for missing API keys. It stops short of rate limits, pagination, or whether list_destinations results can go stale — minor gaps for a query tool.

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?

Labeled sections (BEHAVIOR, PRICING, ACTIONS, USAGE GUIDELINES, ERRORS) make it scannable and the scoping information is front-loaded. Slightly verbose — the pricing line could be folded in — but nearly every line carries actionable content.

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?

There is no output schema and no annotations, yet the description compensates by listing the return fields per action, the cost model, the auth requirement, and the error behavior. An agent has everything needed to call this correctly.

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% with a two-value enum, so the baseline is 3; the description adds real value by documenting what each enum value returns (billing fields vs. dispatch targets) and how list_destinations feeds into alert_manager. It does not constrain format or selection criteria beyond that.

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 precisely what the tool does — a read-only query of ledger states, subscription tiers, and verified notification endpoints — and enumerates the two concrete actions with their return contents. It also names what it is not (alert_manager, market_data), so an agent can distinguish it from siblings without opening the schema.

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 prescribes timing ("Use this tool at the beginning of a workflow to understand available budget and determine valid delivery destinations") and gives two explicit exclusions with the correct alternative named for each. Nothing is left to inference.

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