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

With readOnlyHint already declaring safety, the description adds substantial behavioral context: it is a prerequisite catalog, it lists what data is available, and it constrains runs to kinds and codes present here. It does not discuss freshness, caching, or rate limits, but those are minor for this read-only catalog.

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 front-loaded with the catalog's contents and then closes with two short usage sentences. The first sentence is long and dense with parentheticals, but every clause contributes distinct information about what the catalog contains and how it relates to mcg_quote.

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?

Given zero parameters, no output schema, and a readOnly annotation, the description gives a complete enough picture of what the tool returns and why it matters. It covers the catalog's sections, the prerequisite relationship to mcg_quote, and the consequence of a kind or code being absent.

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 no parameters, so there is no parameter semantics to explain. The rubric's baseline for zero parameters is 4, and the description appropriately does not add irrelevant parameter details.

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 enumerates the catalog's contents (enabled simulation kinds, costed lineage menu, external-frontier graphs, recipes, codes) and distinguishes its role from mcg_quote by stating it must be called first. However, it does not open with a specific action verb such as 'Returns' or 'Lists', so it falls just short of the highest clarity tier.

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 explicitly says 'Call before mcg_quote' and adds 'A kind or code absent here cannot run,' making both when-to-use and when-not conditions clear. It also distinguishes the recipe path by telling the user to pass a recipe's quote object to mcg_quote unchanged.

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