backtest

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

Annotations already declare this as a non-destructive, non-open-world write (readOnlyHint=false, destructiveHint=false). The description adds useful behavior beyond that: it writes predictions and metrics to CSV files as a side effect. However, it says nothing about permissions, runtime, or whether repeated runs overwrite output files.

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 compact sentences with the mechanism and output front-loaded before the return value. No filler, though the trailing 'Returns a backtest id' is somewhat redundant given an output schema exists.

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 value need not be explained, and the description still summarizes it. It conveys the CSV side effects and the cv_id prerequisite; only explicit alternative-tool routing and overwrite/permission behavior are 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 description coverage is 100%, so the schema already fully documents cv_id and the optional plan_id with its null default semantics. The description adds no additional parameter meaning, which matches the baseline 3 when the schema does the work.

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 ('Backtest') and resource ('a plan') plus the mechanism ('with a cross-validation strategy') and the artifact it produces. This distinguishes it from siblings like forecast or compare, though it never names them explicitly.

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?

Usage is only implied: the required cv_id 'Id returned by create_cv' hints that a cross-validation strategy must exist first, but the description gives no explicit when-to-use or when-not-to-use guidance versus forecast, compare, or refine_plan.

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