hcl-mcp

Overview Schema Source Related Servers Discussions Admin

glass_transmissivity

Convert glazing transmittance (Tvis) to Radiance transmissivity for hand-coded glass primitives. Accepts a number or list; use only when writing glass syntax manually, not for material maps or write_material.

Instructions

Convert glazing transmittance (0-1) to Radiance transmissivity. Accepts a number or list.

Transmittance (Tvis, the datasheet number) and transmissivity (the value a Radiance glass primitive takes) are NOT the same: transmissivity is always the larger, e.g. 0.70 -> 0.763.

USE THIS ONLY when hand-writing a Radiance glass primitive. Do NOT pre-convert for write_material(material_type=0) or for an import_geometry material_map {"type": "glass", "tvis": ...} -- both run this same conversion internally, so feeding them 0.763 yields 0.831 (~9% high) and silently inflates every downstream daylight and mel-EDI result. Those two take the raw datasheet Tvis.

The float|list annotation is load-bearing: without it FastMCP emits an empty arg schema and delivers the value as a string, so the core's transmittance-squared term would raise (DEF-1).

Input Schema

TableJSON Schema

Name	Required	Description	Default
`transmittance`	Yes

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 9, 2026

TDQS

A5/5.0

Behavior5/5

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

With no annotations provided, the description fully carries the behavioral burden. It discloses that transmissivity is always larger, gives a numeric example, explains the internal transmittance-squared term, and even warns about the load-bearing float|list annotation and the DEF-1 error. This is far beyond what annotations would normally cover.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is dense but every sentence adds critical value: purpose, definition, usage rule, alternatives with consequence, and an annotation note. It is front-loaded with the core purpose and uses clear formatting (bold 'USE THIS ONLY') to guide the agent. No wasted words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with one parameter, an output schema (which presumably covers return type), and no annotations, the description covers everything an agent needs: what it does, when to use it, when not to, why, and even a technical caveat about schema generation. It is fully self-sufficient.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must fully explain the parameter. It does: 'transmittance' is defined as the datasheet number (Tvis) in the 0-1 range, accepts a number or list, and the conversion logic is detailed. The single parameter is completely documented.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a precise verb and resource ('Convert glazing transmittance to Radiance transmissivity') and immediately clarifies the conceptual difference between Tvis and transmissivity, distinguishing it from any conversion that might be assumed. It also explicitly names the siblings (write_material, import_geometry) that should NOT use this tool, making its role unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives an explicit 'USE THIS ONLY' condition (hand-writing a Radiance glass primitive) and provides a clear negative: do not pre-convert for write_material or import_geometry, with a concrete consequence (9% error). It names alternatives and explains why they take raw Tvis, leaving no room for misapplication.

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