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

With no annotations available, the description fully carries behavioral disclosure: it identifies the tool as internal, explains the cacheControl breakpoint semantics, and states that calling it is a no-op returning an empty object. No behavioral surprises are left undocumented.

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 short and front-loads the critical warning 'LLM should never invoke.' Each sentence adds either a usage constraint, a reason for existence, or the no-op behavior, with no wasted wording.

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 parameterless internal marker with no output schema, the description is fully sufficient: an agent knows not to call it, knows what it is for, and knows what would happen if it did. Nothing required for correct handling is missing.

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 schema has zero parameters, so there is little to document. The description adds the relevant meaning that this is a marker with no arguments and no operational effect, matching the baseline for a parameterless tool.

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 states it is an internal cache-point marker whose invocation is a no-op, and explicitly says the LLM should never invoke it. This is a clear, specific purpose that sets it apart from all sibling tools.

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 explicitly instructs the agent to never invoke the tool and explains its placement-based role at the end of the tools array. For an agent, the correct usage is clear: do not select it.

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