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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is fully covered elsewhere. The description adds only the "custom" qualifier, disclosing nothing about pagination, result size, or what fields each library entry carries.

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 short sentences, front-loaded with the core action and followed by the natural next step. No filler, though the second sentence is a pointer rather than a description of this tool.

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?

This is a simple single-parameter list tool with annotations covering safety and no output schema, so expectations are modest. Still, the description never indicates what a listed library looks like (name, id, timestamps), leaving an agent to discover the return shape only after calling.

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 0% for the single workspace_id parameter, so the description must carry that burden. "in workspace" weakly maps to workspace_id but adds no format, required-ness, or scoping semantics beyond the schema's own required list.

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 uses a clear verb+resource ("List custom transformation libraries") and scopes it to "in workspace," which separates it from the broader list_transformations and the sibling list_rudderstack_transformation_libraries implied by "custom." It does not explicitly name that sibling, so it stops short of a 5.

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 second sentence points to get_transformation_library as the follow-up when code is needed, which is useful sequencing guidance. However, it gives no when-not guidance and never contrasts with list_rudderstack_transformation_libraries, so an agent must infer which list tool applies.

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