sim_attach_model

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

No annotations are provided, so the description carries the full behavioral burden. It does disclose real preconditions (the file must already exist locally, model_name must match the .SUBCKT declaration inside the file, primitive selects the SPICE prefix), but it is silent on mutation semantics: whether the file is copied or referenced, whether the component must already exist, what happens on name mismatch, and whether the change is reversible.

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?

Front-loaded with the action in one sentence, then the usage precondition, then parameters. The Google-style Args/Returns layout is scannable; the Returns block is mildly redundant given an output schema exists, but nothing is padded.

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 4-parameter mutation with no annotations, the description covers all parameters, the file-preparation precondition, and the return shape. The remaining gap is sibling disambiguation against sim_attach_primitives and lib_set_model_* tools, and any failure behavior when the declared name is not found.

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%, so the description must compensate entirely and it does: designator is given an example ('U1'), file_path is defined as the full local path, model_name is defined by how to locate it inside the file ('.SUBCKT <name>' / '.MODEL <name>') and explicitly contrasted with the file name, and primitive's default 'X' plus the D/Q/M alternatives are explained.

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?

States a specific verb and resource ('Attach an external SPICE model file') and enumerates the accepted file formats (.mdl / .ckt / .lib). An agent knows exactly what the call accomplishes 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?

Gives a clear triggering context: 'Use this after fetching a vendor SPICE model file from the manufacturer and saving it locally.' It does not, however, distinguish this from related siblings such as sim_attach_primitives, lib_set_model_name, or lib_set_model_source, so the agent has no routing rule when several model-related tools could apply.

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