list_markets

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

With no annotations supplied, the description carries the full behavioral burden, and it does the most important part: 'Public — no credentials needed' discloses the auth requirement explicitly. It also implies a safe read via 'List'. It does not mention pagination, rate limits, or whether the list is unbounded, which is the only real gap for a zero-parameter read tool.

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, zero waste, and the most decision-relevant fact (deprecation plus replacement) is front-loaded before the descriptive content. Nothing is repeated from structured fields.

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?

For a zero-param public listing tool with no output schema and no annotations, the description supplies the purpose, the returned fields, and the auth posture, which is enough to call it correctly. Minor omissions (pagination behavior, response size) are the only reason it is not a 5.

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 schema baseline of 4 applies. There is nothing parameter-level for the description to clarify, and it correctly avoids inventing filtering options that do not exist.

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 and resource ('List all tradable markets') and enumerates exactly what each entry contains (mark price, 24h change, volume, open interest, funding). It goes further by naming the sibling that supersedes it, so an agent can distinguish it from fetch_markets and fetch_markets_summary without opening a schema.

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 description opens with 'Deprecated: use `fetch_markets_summary`,' which is the strongest possible usage guidance: an explicit when-not-to-use plus the named alternative. An agent reading only this line knows to route away from this tool.

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