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

With no annotations, the description carries the full burden and does so well: it discloses 404 for unknown ids, 400 for invalid arguments before any payment, 503 during data refresh, and that billing occurs only on a 200. Payment mechanics ($0.02 USDC on Base via x402) are stated up front, which is exactly the kind of trait structured fields cannot convey.

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 payload contents lead, then usage context, then operational guarantees — good front-loading. The billing point is stated twice ('charged only for a 200' and 'charged only for a successful answer'), a small redundancy that keeps it from a 5.

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 output schema, the description covers what data comes back, when to reach for it, and how errors and payment behave. It does not describe the shape of the returned payload (e.g. time ranges for price history, units for supply change), which is the main 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% with a regex pattern and examples for `symbol`, so the schema already does the heavy lifting. The description only adds indirectly that unknown ids yield a 404, hinting that lookups must match real symbols, but gives no further constraint beyond the schema.

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 names the exact resource (peg and supply risk of a single stablecoin on Base) and enumerates the payload contents: price history, supply change, mechanism, and holding opportunities. It is clearly distinct from siblings such as get_protocol_risk or get_opportunity_score, though it never explicitly contrasts itself with them.

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 concrete triggering situations — before holding or lending a stablecoin, or when a depeg is suspected — which is more than most tools provide. It stops short of naming alternatives (e.g. use get_protocol_risk for the underlying protocol) or stating when not to call it.

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