Architecture: Dimension Chains

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

Annotations only carry destructiveHint=false, so the description does the heavy lifting and delivers: row ordering, the ISO 129-1 non-duplication rule, the server's own spacing defaults (10 mm then 8 mm) flagged as non-standard, and the temporary DIMSCALE swap that is restored afterwards. These are exactly the behavioral details an agent cannot get from structured fields.

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 main idea is front-loaded and nearly every sentence carries unique information (defaults, restoration behavior, refusals). It is dense and the broken-line layout makes it slightly harder to scan, but there is little filler.

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 an output schema present, return values need no explanation, and the description still covers behavior, defaults, side effects (DIMSCALE restore), and failure modes. Nothing an agent needs to call it correctly is missing.

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 already 100%, so 3 is the baseline, but the description adds real meaning: it clarifies that each chain is drawn at DIMSCALE = `scale` (returned as `dimscale`), that default spacing values are drafting choices, and that sides are validated against unknown/repeated values.

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 names a specific domain resource — the three exterior dimension chains of an architectural plan — and implies the producing verb ('as real DIMENSIONs'). It is clearly distinguishable from generic siblings like dimension_linear or dimension_aligned, but never explicitly contrasts itself against them.

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 concrete preconditions and exclusions ('Refused by name: a drawing with no walls, an unknown or repeated side, a non-positive scale, offset or step') and explains the nearest-first row ordering. It stops short of routing the agent away from sibling dimension tools by name, so it is clear context without full alternative guidance.

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