auto_pack

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

Annotations only supply readOnlyHint=false and destructiveHint=false; the description goes well beyond that with a printer-type precondition and a version-specific no-op failure mode on the Fuse X1, which also implies models are repositioned on success. It stops short of saying what happens to models already positioned or whether the operation is undoable, so it is strong but not exhaustive.

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?

Four compact sentences, front-loaded with the core action and constraints, with no filler. The Fuse X1 parenthetical is verbose but carries real conditional value, so the density is justified rather than padding.

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 zero-required-parameter mutation tool with no output schema, the description supplies the critical preconditions (printer family, machine-type prefix, server-version caveat) and enum semantics. Remaining gaps are the three numeric parameters and any statement of return behavior or post-pack state, which are secondary here.

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 only 20%, with just scene_id documented in the schema, yet the description explains packing_mode's two enum values in operational terms (PACK_HEIGHT minimizes build height for faster printing; PACK_VOLUME is tightest). It adds no meaning for seed, model_spacing_mm, or distance_from_wall_mm, leaving three of five parameters undocumented anywhere.

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 concrete verb+resource ('Pack all models into the 3D build chamber') and immediately scopes it to SLS printers, distinguishing it from the SLA-oriented sibling auto_layout and from the fill_build_* tools. An agent can identify the operation 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?

Explicitly gives the when (SLS machine types starting with FS or PILK), the when-not (Fuse X1 / FUSX-1-0, where PreFormServer 3.63 refuses packing), and the alternative to use instead (auto_layout for SLA). This is about as complete as conditional routing guidance gets.

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