Extract displacement, velocity, or position for specified nodes from a d3plot at a 1-based state using safe reader tools. Provide d3plot path, node IDs, quantity, state, and units.
Extract native position/displacement/velocity at a 1-based state. Older unverified vector ABIs are blocked; use explicit reader tools.
| Name | Required | Description | Default |
|---|---|---|---|
| state | Yes | ||
| units | Yes | ||
| d3plot | Yes | ||
| node_ids | Yes | ||
| quantity | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It usefully discloses a 1-based indexing convention and warns that older vector ABIs are blocked, but says nothing about permissions, failure modes, return format, or what units must be supplied.
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 short sentences with the core action front-loaded and no filler. It is appropriately sized, though the second sentence is a vague warning that could be sharper.
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 tool with 5 required parameters, no annotations, no output schema, and 0% schema coverage, the description is far too thin. An agent lacks the units vocabulary, quantity vocabulary, d3plot path expectations, and any sense of the return shape.
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 0% and all 5 parameters are undocumented in both places. The description clarifies only the state index convention and hints at quantity values (position/displacement/velocity), leaving d3plot, node_ids, and especially the units string (accepted values?) unexplained.
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 (extract) plus the resource (native position/displacement/velocity at a 1-based state), which is clear enough to distinguish from history-style siblings like extract_node_history. However, it never names the actual related tools (extract_d3plot_nodal, extract_lsreader_nodal), so differentiation relies on inference.
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?
It gives one exclusion (older unverified vector ABIs are blocked) and a generic pointer ("use explicit reader tools"), which implies when to reach for alternatives but names none of them. Usage is implied rather than stated with concrete alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.