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

Annotations only declare the safety profile (readOnlyHint=false, non-idempotent, non-destructive, closed-world); the description adds substantive behavior: each idea is generated AND backtested, the result is a paper preview rather than a KEEP, identical-script inputs are rejected, and payment cannot alter the verdict. The cryptic header '(sealed:false, is_keep:false, paper:true)' and 'Payment never changes a verdict' imply billing without explaining cost/quotas, keeping it just under a 5.

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?

Dense and front-loaded: purpose and the verdict-alternative come first, then refusal condition and billing caveat. Minor waste from the unexplained '(sealed:false, is_keep:false, paper:true)' token and 'Not a KEEP' repeating the is_keep flag, but no sentence is filler.

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 an output schema present, return-shape explanation is not required, and the description covers purpose, refusal, and the verdict alternative. However, for a 5-parameter tool it leaves asset and style_a/style_b semantically unexplained, and the dollar/payment reference is introduced without saying what it costs - a gap an agent deciding whether to invoke would trip on.

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 60% - idea_a/idea_b and asset are documented in the schema, while style_a/style_b have no descriptions at all. The description clarifies only that the two ideas are free-text strategy descriptions to be generated and backtested; it says nothing about the asset param or the style defaults (mean_reversion / trend), so it does not compensate for the uncovered half.

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 and scope: 'Pit two public ideas against each other: generate + backtest each, return a compact comparison.' It also flags the output class (PAPER PREVIEW) and explicitly differentiates itself from get_lab_desktop_handoff, so an agent can tell verdict-seeking apart from comparison.

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?

Names an alternative for the verdict case ('for a verdict use get_lab_desktop_handoff') and gives a hard precondition for refusal ('Refuses two ideas that produce the same script'). It stops short of routing to the other adjacent siblings such as backtest_arenascript or invent_and_backtest, so routing coverage is partial rather than exhaustive.

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