Assign a filament spool to a printer (or a specific extruder slot).
| Name | Required | Description | Default |
|---|---|---|---|
| source | No | ||
| extruder | No | ||
| printer_id | Yes | The printer ID | |
| filament_id | Yes | The filament IDs (comma-separated for multiple) |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations indicate this is a mutation (readOnlyHint: false) but provide no further safety details. The description adds only the nuance about targeting an extruder slot; it does not disclose consequences like overwriting existing assignments or side effects of the 'source' parameter.
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 a single concise sentence that front-loads the core purpose. Every word is necessary and there is no redundant information.
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?
With 4 parameters, no output schema, and no explanatory detail on source or extruder, the description is too minimal. It does not inform the agent about required context fields or what the operation returns, making it incomplete for a tool with this complexity.
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 50%, and the description does not compensate. It mentions 'printer' and 'extruder slot' but not the 'source' or 'extruder' parameters. The filament_id description is confusing, as its schema type is integer but it says 'comma-separated for multiple'.
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 uses a specific verb ('Assign') with a clear resource ('filament spool') and target ('printer (or a specific extruder slot)'). It clearly distinguishes from sibling tools like unassign_filament and adjust_filament_weight.
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 when to use this tool - when you need to assign a filament to a printer. However, it does not explicitly mention alternatives or exclusions, such as using unassign_filament to remove assignments, so guidance is implied rather than explicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Most tools are clearly separated by resource and action, but several overlapping queue-related tools exist—get_next_queue_item vs get_next_queue_items_for_printers, list_queue vs list_pending_queue_items, and inspect_printer_queue—which could cause misselection. list_custom_fields vs list_custom_fields_for and add_to_queue vs create_print_job add further ambiguity.
Names overwhelmingly follow a verb_noun snake_case pattern with consistent resource nouns like print_job, queue_item, folder, and filament. Minor inconsistencies exist, such as add_to_queue vs create_folder/create_print_job, save_queue_group vs update/create, and the slightly odd home_printer and send_back_for_revision.
With 74 tools, this is far beyond the recommended MCP server size and makes the toolset unwieldy to navigate, even for a broad domain. This clearly falls into the extreme 50+ tool category.
Core operational workflows—queue, print jobs, files, filament, and printer control—are well represented. However, printer lifecycle management is missing (no add/update/delete printer), and maintenance management is limited to a read-only dashboard with no corresponding actions.
