Describe the simulator

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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint=false, so safety is covered; the description goes further by disclosing that it "takes no arguments, runs no market and returns the same text on every call," which is genuine behavioral context (deterministic output, no side effects on simulator state). It stops short of saying anything about the size/format of the returned text, which is acceptable given the output schema exists.

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 scope enumeration is front-loaded in the first sentence, followed by the single usage instruction and the no-arguments/determinism caveat. Every clause carries information; nothing is padded.

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 zero-argument documentation tool with an output schema present, the description covers scope, invocation order, and determinism, which is everything needed to select and call it. Return-value structure is correctly left to the output schema rather than duplicated.

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?

Zero parameters, so the baseline is 4; the description's statement that it "takes no arguments" is consistent with the empty schema and removes any doubt about needing input.

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?

States a specific verb (describe) and an enumerated scope: what the simulator is, what its realism checks certify, what it cannot do, tool caps, and run duration. This is unmistakably distinct from every sibling (validate_strategy, run_stress_scenario, etc.), which are action tools rather than meta-documentation.

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?

"Call it first in a session, before any other tool" is an explicit, unambiguous ordering instruction that tells the agent exactly when this tool applies. No alternative needs to be named because it is a prerequisite orientation call rather than a competing workflow.

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