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

It adds real context beyond the annotations: it discloses the data coverage (US stocks and ETFs, spot crypto, FX, gold and silver; daily and intraday bars), that no external price download is needed, and what the response will contain. The readOnly/openWorld annotations already cover the safety profile, so the remaining gap is minor.

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?

Front-loaded with the action ("Start here") and packed with decision-relevant facts in two sentences with no filler. Every clause — data coverage, no-download guarantee, return contents, next tool — earns its place.

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?

A zero-parameter discovery tool with an output schema and readOnly annotations; the description supplies the domain scope, the sequencing, and the value proposition. Nothing an agent needs to decide to call it, or what to do next, is 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?

The tool takes zero parameters, so the description is not required to explain any argument semantics. There is nothing further to add here.

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 concrete verb and resource set: it returns the markets and bar sizes served, the backtest rules, and how to write strategy code. It also distinguishes itself from siblings by naming create_study as the follow-up step, so an agent knows this is the orientation tool rather than a backtest runner.

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?

"Start here" plus "then call create_study" gives an explicit entry point and a named next tool, which is clear routing. It stops short of stating whether this call is mandatory before create_study or merely recommended, and gives no exclusions for when to skip it.

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