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

Annotations already declare readOnly/idempotent/non-destructive, and the description goes well beyond them: accepted input format (text DXF from AutoCAD/Fusion/Inventor), the assumption of flat 2D geometry, the exact diagnostics reported, and the explicit scope limit that nesting is excluded. That is meaningful behavioral context an agent could not infer from the annotations.

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 dense sentences, front-loaded with the core action and outputs, then the conditional extensions and the scope exclusion. No filler or restatement of the title.

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 10 parameters, nested objects, and no output schema, the description carries the return-value burden and does so by listing the result fields and the two conditional result modes. Minor gaps remain around units handling and failure behavior on malformed files, but nothing essential to invoking 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 90%, so baseline is 3; the description still adds value by explaining the conditional relationship between inputs and outputs (cut_speed → time with acceleration and pierces; pricing → price). It does not clarify units fallback, pierce_time_s, or quantity, but the schema already documents those.

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 and resource ('Reads a flat 2D DXF') and enumerates the concrete outputs (parts, cut length, pierces, drawing problems), so an agent knows exactly what it gets back. It also scopes the tool negatively ('Sheet nesting is not included'), separating it from nesting tools, and its domain is clearly distinct from the STL/G-code/rates siblings.

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?

Conditional usage is spelled out well: 'With a cutting speed it also returns the cutting time... with pricing it returns a price', which tells the agent which optional inputs unlock which behavior. 'Sheet nesting is not included' is a useful exclusion. No sibling alternative is named explicitly, which keeps it from a 5.

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