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

With no annotations the description carries the full burden, and it does disclose important behavioral traits: refusal with no charge when the live price-history source is unavailable, plus a concrete price point (x402: $0.04 USDC per call) and a settlement proof artifact (kind 30120). Return format, latency, and rate limits remain undisclosed.

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 purpose is front-loaded and the sibling routing is efficient, but the refusal condition is stated twice in near-identical sentences ('when live price history cannot be fetched' / 'when the required source (live price history) cannot be fetched'), which is wasted space and reads as an editing artifact.

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 single-parameter tool with no annotations and no output schema, the description covers purpose, alternatives, failure/pricing behavior, and a settlement-proof reference. It stops short of describing what the volatility read actually returns, which is the one remaining gap.

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% for the single 'task' parameter, so the baseline is 3. The description adds no meaning to that parameter, and its mention of 'configurable alert thresholds' is not represented in the schema, so it does not enrich parameter understanding.

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 ('Real-time volatility read for a trading pair') and explicitly differentiates from two siblings: alert-generator 'fires the alert' and historical-analysis 'explains the trend behind the number.' An agent can select this tool without opening any 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?

Names two alternatives with the role each plays, which gives clear context for choosing this tool. It does not, however, address other plausible siblings like oracle.price-feed or crypto.market-analyzer, and gives no exclusions for when NOT to use it.

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