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

Annotations declare the safety profile (readOnly=false, destructive=false, idempotent=false, openWorld=false), so the description is free to add real context — and it does: in-sample only, no holdout, and 'Renvoie les mêmes métriques, limites et quota' sets expectations about results and quota consumption. The lack of any warning about in-sample overfitting risk is a minor gap.

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?

Three short sentences, front-loaded with the alias relationship and then the execution scope, followed by the submission caveat. Dense but every clause carries information; no 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, the return values need not be enumerated, and the description still gestures at them (mêmes métriques, limites, quota layer). Safety and privacy constraints are covered. The only thing an agent might still want is explicit guidance on choosing this over backtest_strategy.

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% for the single 'arenascript' parameter, so the schema already carries its meaning and the 20,000-char limit. The description adds a submission constraint (public scripts only) but no syntax or format detail beyond the schema, so the baseline 3 holds.

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?

Specifies the verb/resource (backtest, an ArenaScript) and immediately pins the relationship to a sibling: 'Alias de backtest_strategy'. It then scopes the execution precisely (moteur Rust du Lab, bougies OHLCV du serveur, timeframe déclaré, échantillon, sans holdout), which is enough to tell it apart from invent_and_backtest and the other backtest-adjacent siblings.

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 alias statement tells the agent this is interchangeable with backtest_strategy, and 'Le script public peut être conservé; ne pas soumettre de stratégie privée' gives a concrete do/don't for submission. It does not, however, state when to prefer this over backtest_strategy or invent_and_backtest, so the routing is implied rather than explicit.

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