mmar_list_scene_instances

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

With no annotations, the description carries the full burden. It discloses that it returns an array of SceneInstance objects with UUIDs, names, and content, which is useful. However, it does not mention whether a session is required, potential error behaviors, or if the list could be empty, leaving some behavioral context implicit.

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 two concise sentences, front-loaded with the purpose and followed by the return format. There is no redundant or extraneous information, making it efficient and well-structured.

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 simple list operation with one parameter and no output schema, the description provides adequate context: it states that all instances are listed and describes the return fields. It could mention authentication requirements or the possibility of large result sets, but overall it is sufficient for an agent to understand the tool's role and output.

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 input schema already provides 100% coverage for the single parameter, including a description of the scene_type_uuid. The tool description adds no further parameter context, so the baseline of 3 is appropriate given the schema's completeness.

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 clearly states the action (List), the resource (model instances/diagrams), and the scope (for a specific SceneType). It distinguishes this from sibling tools like mmar_list_scene_types (which lists the types themselves) and mmar_get_scene_instance (which retrieves a single instance).

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 implies that a scene_type_uuid is needed to list all instances for that type, suggesting a workflow of first listing scene types. However, it does not explicitly state when to use this tool versus mmar_get_scene_instance or other alternatives, nor does it mention any exclusions or prerequisites like authentication.

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