lib_get_personal_library_uuid

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds real behavioral value by disclosing that the call returns undefined on private deployments, an edge case not captured by annotations and useful given no output schema exists.

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?

A single tight sentence with the core purpose front-loaded and the caveat parenthetically appended. No filler or redundancy to trim.

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?

With full annotation coverage, a fully documented parameter schema, and only one trivial argument, the description covers what an agent needs, including the private-deployment caveat. It could optionally note the UUID's format or relationship to the other library-UUID tools, but nothing essential 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?

Schema description coverage is 100% for the single instance_id parameter, and the schema already explains the 8-char hex format and the omit-when-single-instance rule. The description adds nothing beyond that, so the baseline 3 applies.

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 a specific verb (Get) and a precise resource (the user's personal library UUID), which is self-differentiating from the nearby lib_get_system_library_uuid and lib_get_project_library_uuid siblings by the 'personal' qualifier alone. An agent can tell exactly what it retrieves without opening the schema.

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 resource name implies when to use it (when you need the personal library's identifier), but there is no explicit when-to-use/when-not guidance or reference to the system/project library UUID alternatives in the sibling set. Usage is inferable but not stated.

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