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

Beyond the readOnlyHint annotation, the description discloses important runtime behavior: missing required facts throw, the engine never defaults to 0, facts can come from input or prior actions, and only SET_FACT creates a fact from nothing. It also notes the data is static and safe to cache, giving the agent actionable operational knowledge.

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 core purpose and uses a concrete example to clarify subtle semantics. It is somewhat long, but each sentence contributes real value—especially the factRequired flag clarification and the failure behavior—so the length is justified.

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 no-input, read-only metadata endpoint, the description is largely complete: it explains what is returned, gives an example, defines the key flag, and warns about runtime failure. Since there is no output schema, a full enumeration of the response shape would improve completeness, but the invocation path is fully clear.

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?

This tool takes zero parameters, so there is nothing for the description to clarify about arguments. The baseline for zero-parameter tools is 4, and the description appropriately focuses on the returned concept of fact requirements rather than input handling.

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 opens with a specific verb and resource: 'Retrieve runtime fact requirements per Action type.' It goes on to explain exactly what kind of information is returned, distinguishing this metadata lookup from companion fact-management tools like lexq_facts_list or lexq_facts_create.

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 makes the intended use case clear: an agent needs to know which facts must be present in an execution payload for a given Action type. It does not explicitly name an alternative tool or state when not to use it, so it stops short of a perfect score, but the context is strong enough to guide selection.

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