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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and openWorldHint=false, so the safety profile is covered. The description adds 'Free.' and lists returned categories, which is useful behavioral context, but 'Never: —.' is opaque and no auth or rate-limit details are given. A 3 reflects moderate added value against already-rich annotations.

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?

The description is very short and front-loads the returned categories. However, the fragmented style and the unhelpful 'Never: —.' note reduce structural clarity. It is concise but cryptic in places.

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 simple, read-only discovery tool with rich annotations and no output schema, the description covers the main return categories and optional trade usage. But it leaves 'gate' and 'Never: —.' unexplained, so an agent may still have minor questions. Adequate but not fully complete.

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% and the single optional 'trade' parameter is fully described in the schema. The description essentially repeats the schema's note that a trade yields field knowledge. With high schema coverage, baseline 3 is appropriate.

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 the specific resources the tool exposes: catalog, schemas, fees, gate, and error codes, plus optional field knowledge for a trade. This is more than restating the name 'discover' and gives a clear sense of the tool's domain. However, it does not explicitly differentiate itself from siblings like fetch or search, so it stops short of 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?

It notes that supplying a trade yields field knowledge for it, which is a usage hint for the single parameter. But there is no guidance on when to choose this tool over alternatives such as fetch or search, and no prerequisites or exclusions beyond a cryptic 'Never: —.'

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