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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false; the description reinforces this with 'Read-only' and adds 'No key needed.' It also discloses behavior beyond the schema: what the JSON response contains, and that unsupported methods return offered=false with a reason. This gives the agent a clear model of side effects and output shape without needing a sample.

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 dense but every sentence earns its place: purpose, output format, when-to-use, exclusions with alternatives, and response details are all packed in without fluff. Key info is front-loaded, with the 'Read-only' and 'No key needed' notes at the end as low-priority confirmations.

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?

For a read-only quoting tool with no output schema, the description is fully self-sufficient: it explains what the tool does, the exact response fields, the special case for unoffered methods, authentication expectations, and usage boundaries. There is no critical information an agent would need to correctly select or invoke this tool that 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 100%, so the baseline is 3codified. The description goes beyond the schema by defining the semantic relationship between 'lane' and the tier parameter ('a lane = a price tier: cheap, balanced, fast') and clarifying the meaning of 'units' (standard 1, heavy 2). While it doesn't detail each parameter, it adds meaningful conceptual context that helps set tier correctly.

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 opens with a specific verb ('Quote') and a clear resource (a JSON-RPC call's cost), and defines what it returns: weighted units and USD per 1M units per tier. It explicitly distinguishes itself from sibling tools by naming get_prices, list_plans, and get_billing_status as alternatives for other quote-like questions, so an agent can disambiguate immediately.

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?

It gives explicit when-to-use guidance: when an owner asks what a workload would cost or before calling a heavy method. It also provides direct exclusions with named alternatives ('Not for gas or token prices (use get_prices), plan prices (use list_plans) or your own balances (use get_billing_status)'), leaving no ambiguity about routing.

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