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

Annotations already mark this as destructive; the description goes further by explaining the exact scope of destruction: the association is severed, but snapshot values persist and the line becomes an ordinary assumption. It also discloses the read-only API key restriction, which is not visible in 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?

Two concise sentences, with the core action front-loaded and behavior/auth limitations placed after. Every sentence adds value without redundant restatement of the title or schema.

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?

Between the schema and description, the agent knows what the operation does, which fields are required, and the auth constraint. The lack of an output schema is not a major gap because the resulting state is clearly described, though there is no explicit success/failure or reversibility detail.

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 schema already documents `uid`, `summary`, and `model_id` in detail. The description's mention of `uid` merely echoes the schema and adds no new parameter semantics.

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 a specific verb ('Detach'), a resource ('external reference'), and the selection key (`uid`). It also clarifies the outcome in a way that distinguishes unlink from delete or re-link 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?

The description implicitly tells an agent when this tool applies: when an external reference should stop following its source. However, it never names alternatives (e.g., layerz_external_ref for re-linking) or explicit when-not conditions. The only stated restriction is read-only API keys, which is an auth boundary rather than a usage-routing rule.

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