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 the values are historical frequencies, not forecasts, explains the validation against Polymarket quotes, and notes that the model is built on ES while other symbols are only descriptive.

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 front-loaded with the definition and every sentence contributes useful usage or trust information. It is somewhat long, especially the Polymarket validation detail, but that detail directly shapes when the tool should be trusted.

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 tool with only two parameters and no output schema, the description supplies all critical operating context: what it computes, how levels are measured, limitations, availability, and quota relationship to a sibling. No essential selection or invocation detail is missing.

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%, so the baseline is 3. The description adds value by explaining that distances are measured in units of today's ATR from the first 90 minutes, which gives the agent meaningful context for interpreting the levels parameter 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 states exactly what the tool computes: the probability that today's US regular session close prints above any set of price levels. The wording is specific and distinct from the sibling tools, making the core purpose unambiguous.

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 explicitly tells the agent to use this tool for shape and tails, not direction, and warns that near-the-money prediction-market prices were more accurate. It also states when the tool becomes available (90 minutes into the session), which is directly actionable.

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