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

Annotations already mark the tool as read-only, idempotent, and non-destructive. The description adds meaningful behavioral detail by specifying that it reads from request headers or environment variables and which exact variables are used. This goes beyond what annotations state, though it does not cover edge cases like missing variables or precedence.

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 compact and well-structured: a WHEN clause, the mechanism, and a direct usage directive. Every sentence earns its place and the most important usage context is front-loaded.

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 simple, zero-parameter, non-destructive lookup tool, the description covers when to use it, what it reads, and how it relates to other tools. It does not specify the exact return shape, but the description's mention of knowing folder(s) is adequate for agent invocation; an explicit output contract would make it fully complete.

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?

The tool has zero parameters, so schema coverage is trivially 100% and there is nothing to document. The description compensates by explaining what information the tool resolves, which is sufficient for a parameterless lookup.

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 clearly states the tool's purpose: determining which folders are configured as workspace/project roots for the current caller. It names the exact configuration keys read (D365-Custom-Model-Path and D365-Standard-Model-Path), making the behavior specific and distinguishable from sibling tools.

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 opens with 'WHEN' and gives explicit guidance: use this tool before any tool accepting customModelPath/standardModelPath. This directly tells an agent when to invoke it and frames its role as a prerequisite helper, which is clear usage guidance.

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