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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description adds two things they cannot: that the call is free (no billing impact) and that paper money is simulated with no real orders. That no-real-orders guarantee is exactly the kind of reassurance an agent needs before acting on the result; it only lacks any note on freshness or caching of the status 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?

Two short sentences with no filler, and the field list is front-loaded. The colon-fragment structure ('Paper trading for the caller: enabled, can_start, ...') is terse to the point that 'status' and 'entry_ready' are only loosely explained, but nothing is wasted.

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 zero parameters and an output schema present, the description does not need to document return values, and it correctly focuses on the cost and simulation semantics. The only real gap is routing guidance among the many sibling paper-trading tools, which is a usage gap rather than a completeness failure.

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 takes zero parameters, so the baseline applies and there is nothing for the description to disambiguate. No parameter noise is introduced.

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?

Identifies the resource (paper trading status for the caller) and enumerates the fields the caller gets back (enabled, can_start, has_account, entry_ready, status), which makes the tool's output purpose unambiguous. It does not distinguish itself from near siblings like get_paper_account or get_account, so an agent must infer the boundary.

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?

There is no when-to-use guidance at all: no statement that this is the pre-flight check before creating an account or starting a strategy, and no contrast with get_paper_account, get_account, or get_paper_catalog. The presence of these siblings makes the omission costly.

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