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

With no annotations, the description carries the full transparency burden. It discloses that intervals are calibrated, describes the band output, and explains the alpha default and meaning. However, it does not mention potential failure modes, required preconditions (e.g., existing forecast), or any additional behavior like caching or error handling, leaving some ambiguity for a tool with no structured safety annotations.

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 two sentences, front-loaded with the core function and immediately followed by usage guidance. No redundant phrases, every word earns its place, and it is appropriately sized for the tool's simplicity.

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 the tool's simplicity (2 params, no output schema, no annotations), the description is mostly complete: it states output (lower/upper band), key parameter semantics, and usage triggers. It lacks explicit return field names or error conditions, but the 'lower/upper band' phrasing provides a sufficient mental model for an agent. This is adequate but not exhaustive, earning a 4.

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 schema covers 50% of parameters (ticker has a basic path description, alpha lacks description). The description compensates by explaining alpha as 'miscoverage alpha (default 0.1 = 90% interval)' and clarifies ticker's role via 'one ticker's forecast'. This adds meaningful context beyond the schema, though it does not go into detailed format or edge cases.

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 returns conformal prediction intervals (calibrated lower/upper band) for a single ticker's forecast, with specific reference to the miscoverage alpha. It explicitly contrasts with point estimates, distinguishing it from prediction tools, and specifies scope (one ticker). This is a specific verb+resource description that effectively communicates the tool's function.

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 provides explicit when-to-use guidance: 'Call it when the user asks how confident is the model? or wants an uncertainty range around a prediction rather than just a point estimate.' This is clear context, but it does not explicitly name alternative tools or state when not to use it, so it falls short of a 5.

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