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

While annotations already declare readOnlyHint and idempotentHint, the description adds crucial behavioral context: it 'refuses every tool that could change data, on every instance' and therefore never needs user approval, and the signed-in user's F&O roles and legal entities apply. These are meaningful operational details beyond what the annotations convey.

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 front-loaded with the WHEN condition, followed by scope, safety behavior, prerequisite discovery step, and the alternative tool. Every sentence carries unique signal, and there is no wasted text.

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 read-only generic dispatcher with three well-documented parameters and annotations covering safety, the description contains everything an agent needs: scope, permission model, sibling differentiation, refusal behavior, and the prerequisite to call erp_list_tools. No output schema is needed because the return is tool-dependent and the description does not imply otherwise.

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 100%, and the schema fully documents the instance, tool, and arguments parameters. The description only reinforces that it takes the same arguments as erp_call and that the tool name must come from erp_list_tools, without adding syntax or format details beyond the schema. The baseline of 3 is appropriate when the schema does the heavy lifting.

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 states a specific verb and resource ('READ from ONE Dynamics 365 F&O instance') and clarifies the scope of operations (look up entities, query data, open forms to read). It explicitly differentiates itself from erp_call, so an agent can select the correct tool without opening the schema.

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 provides explicit when-to-use guidance: use erp_read for reads, use erp_call only for changes the user asked for, and call erp_list_tools first to discover tool names. The condition that selects each sibling is stated directly, leaving nothing to inference.

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