open_model

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

With no annotations, the description carries the full behavioral burden. It does add one meaningful behavior detail: 'Set read_only=true to prevent modifications.' But it does not disclose what happens by default, what side effects opening a model may have, whether it registers the model as open, or what fields the returned 'info' includes.

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 sentences with no filler. The core action and file formats come first, and the read_only guidance is front-loaded as an imperative. Every clause earns its place.

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 two-parameter tool with no output schema, the description covers selection, file scope, and the read-only mode. It is slightly vague about what 'its info' contains, but an agent can likely invoke the tool correctly with just the path and the read_only guidance provided.

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 0% description coverage, so the prose must add meaning. The description clarifies that path points to a PowerDesigner model file with supported extensions, and it explicitly explains the read_only parameter's effect. This is meaningful compensation for the schema's lack of parameter descriptions.

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 action ('Open'), a specific resource ('PowerDesigner model file'), and the supported formats (.pdm/.cdm/.ldm), and states the outcome ('return its info'. This distinguishes it clearly from sibling tools like close_model, create_model, or get_model_info.

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 intended use is implied: open a model file when you want its info, optionally read-only. However, it never explicitly explains when to choose open_model over alternatives like get_model_info, list_open_models, or create_model, nor does it mention exclusions or prerequisites.

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