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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false), so the bar is lower. The description adds genuinely useful context beyond that: the internal structure of the response and a stated limitation (the current-catalog/survivorship caveat and missing-data handling), which is exactly the kind of caveat an agent needs to interpret results correctly.

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 sentences, front-loaded with the resource and its scope, then the methodology payload. Every clause carries information. It is dense and list-heavy in the back half, which slightly reduces readability, but there is 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 no parameters and no output schema, the description carries the burden of describing what comes back, and it does so well by naming the per-surface fields and the methodology contents. A fuller account of the response shape (e.g., the container/key names) is the only missing piece.

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 is 4 per the rubric. There is nothing for the description to compensate for, and it does not waste words inventing parameter guidance.

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?

The description states a specific resource (the platform's five backtest surfaces) and enumerates exactly what is returned for each: the question it answers, its page, API endpoints, auth, and methodology details. This is far more concrete than a tautology. It stops short of a 5 because it never distinguishes this tool from a sibling like get_backtest_models, leaving the agent to 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?

Usage is implied — an agent should call this to discover and compare the five backtest surfaces — but there is no explicit when-to-use, when-not-to-use, or named alternative (e.g., get_backtest_models). The clause 'All five are current — none supersedes another' usefully tells the agent not to pick among them, which nudges it above a bare 2.

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