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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is fully covered. The description contributes the field-level scope (state, leverage, fees, trading rules) and the word 'Every' implies an unfiltered full snapshot with no pagination, which is useful context. It does not address freshness or whether delisted markets are included, beyond the vague 'state' field.

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 short sentences: the payload is front-loaded first, then a natural-language usage anchor. No filler, no repetition of the title or annotations.

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 zero parameters, rich annotations and an output schema that carries return structure, the description does the small amount of work required. The only residual gap is indicating whether inactive/delisted markets appear and how fresh the snapshot is, which slightly matters for a market catalog.

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 of 4 applies. The description correctly implies no filtering inputs exist by promising 'every market', which matches the empty schema.

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 names a concrete resource (every market the network lists) and enumerates the payload dimensions: state, leverage, fees, and trading rules with tick/lot/minimum size. That is far more specific than a restated title. It stops short of explicitly differentiating from near neighbors like get_fees, so a 4 rather than a 5.

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 embedded prompt 'Which markets can I trade?' implies the retrieval scenario and hints that results are tradable-market oriented. There is no explicit when-not guidance, no mention of alternatives such as get_fees or get_orderbook for narrower questions, and no stated prerequisites.

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