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 names the three emitted flags, declares the facts-only/never-advice policy, and discloses rate limits (3 calls/hour per IP, shared with the website) plus the paid path ($0.030/call over x402). This is exactly the behavioral context an agent needs and cannot get from structured fields.

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 operational content is front-loaded and the later sentences (policy, pricing) are terse. The opening sentence is somewhat convoluted with stacked parentheticals, but overall it is appropriately sized for the information conveyed.

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?

With no output schema and no annotations, the description compensates by explaining what the returned flags mean and the cost/access model. It leaves minor gaps such as behavior on an unknown symbol, but an agent has enough to call it 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% and the single parameter is fully documented ('Stablecoin symbol (e.g. USDC) or CoinGecko id'). The description only refers to 'this stablecoin's' without adding format or resolution detail, so it adds nothing beyond the schema. Baseline 3 is correct.

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 assesses: whether a stablecoin's $1 peg is a hard redemption/arbitrage anchor or a soft peg, and whether it is currently dislocated. The resource (stablecoin peg) and analytical output (SOFT_PEG, BROKEN_HISTORY, DISLOCATION) are specific. It does not explicitly differentiate itself from the sibling 'safety' tool, which is the only gap.

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?

Usage is implied by the question the tool answers — reach for it when judging a stablecoin's peg integrity — but there is no explicit when-to-use statement, no when-not, and no named alternative among siblings like 'safety' or 'exit_cost'. The agent must infer the routing.

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