open_workbook

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

With no annotations, the description bears full responsibility. It discloses the 'no duplicate' behavior and the prerequisite of Excel running. It does not mention side effects or error handling, but for a simple open operation these are adequately covered.

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 two sentences: first states the core purpose, second adds behavioral details. No redundant information; efficiently 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?

Given the tool's simplicity (one parameter, no nested objects), and presence of output schema, the description covers prerequisites, duplicate handling, and file types. It is complete for its complexity.

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% for the only parameter 'path'. The description reiterates the absolute path requirement without adding semantic value beyond the schema's example. Baseline is appropriate.

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 opens a workbook (.xlsx/.xlsm) from disk for use by other ModelRisk tools. It specifies the verb ('Open'), resource ('workbook'), and distinguishes from siblings by noting it is the gateway for subsequent actions.

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 instructs to pass an absolute file path and notes the behavior when a duplicate is open (returns existing). It does not explicitly list when not to use or compare to alternatives, but the context of being a prerequisite for other tools is clear.

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