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

With no annotations, the description carries the full behavioral burden. It discloses that the operation mutates fields and that the id cannot be changed, but it does not explain merge vs. replace semantics, behavior on unknown fields or nonexistent parts, error conditions, response shape, or any required forge state. The id-immutability note is the only meaningful added behavioral detail.

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 sentence with no filler. The core action, target resource, and key constraint are all present and immediately readable. Every word 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?

There is no output schema and no annotations, so the description alone must prepare the agent. It omits return behavior, error handling, update semantics, and preconditions beyond the schema's forge_handle hint. For a mutation tool with three required parameters, this is incomplete.

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 coverage is 67%, so the description adds some value by mapping 'changes' to part fields and clarifying that id is immutable. However, it does not enumerate valid field names, value formats, or whether changes is a partial update, and the schema itself only provides one example.

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 states a specific verb ('change'), a resource ('fields of an existing part'), and a key constraint (anything but its id). It does not explicitly name sibling tools, but 'existing part' communicates enough contrast with forge_add/forge_remove for an agent to infer its role.

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 phrase 'existing part' implies this tool is for modifying an already-created part rather than adding or removing one. However, it provides no explicit guidance on when to choose this over siblings like forge_add, forge_keyframe, or forge_observe, leaving the decision mostly to inference.

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