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

With no annotations, the description carries the full burden. It discloses that the data is versioned, refreshed hourly, and costs $0.001 (with payment details), plus an HTTP twin for alternative access. This is valuable behavioral context beyond a simple registry lookup, though it doesn't explicitly state read-only status.

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 front-loaded with the use case, then efficiently lists registry contents, cost, and HTTP twin. Every sentence adds useful information without unnecessary fluff, though it is somewhat lengthy due to the detailed data field enumeration.

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?

Given no output schema and no parameters, the description does a good job of specifying what the registry contains (wrapped/unwrapped addresses, ERC-1155 vault, ISIN, TradingView symbol, listed flag) and provides cost and update frequency. It doesn't detail the output format, but the agent can infer it returns a structured list. Missing only explicit instructions on how to interpret or use the returned data.

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?

The tool has zero parameters, so the baseline is 4. However, the description's phrasing ('resolve a stock ticker', 'check whether a contract') implies an input, yet the schema is empty. It does clarify it's a 'complete issuer registry' for all names, suggesting it returns a full dump, but the mismatch between implied input and no parameters could confuse an agent. The description doesn't compensate for this ambiguity.

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 clearly states the tool's function: resolving a stock ticker to its ST0x on-chain token or verifying a contract. It identifies itself as the complete issuer registry across four chains, listing key data fields. This differentiates it from sibling tools like st0x_pulse or st0x_premium, which likely handle market data or premium features.

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?

The description explicitly opens with 'Use this when you need to...' and specifies two concrete scenarios (ticker resolution and contract verification). While it doesn't explicitly mention alternatives, the conditions are clear enough for an agent to decide when this tool is appropriate.

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