excel_open_file

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. 'Open an existing Excel file' implies a read operation, but it doesn't specify whether this is read-only, if it requires file permissions, what happens on failure (e.g., file not found), or if it modifies the file. For a tool with zero annotation coverage, this leaves critical behavioral traits undocumented, though it doesn't contradict any 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?

The description is a single, direct sentence with zero wasted words. It's front-loaded with the core action and resource, making it easy to parse quickly. Every word earns its place by conveying the essential purpose without unnecessary elaboration, which is ideal for conciseness in a simple tool like this.

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 complexity (a file operation tool with no annotations, no output schema, and low schema coverage), the description is incomplete. It doesn't address what 'open' entails behaviorally, what the output might be (e.g., a workbook handle or data), error conditions, or usage context. For a tool that interacts with files, more detail is needed to ensure the agent can use it correctly without guesswork.

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 input schema has one parameter 'filePath' with 0% description coverage, so the schema provides no semantic context. The description doesn't mention parameters at all, failing to compensate for the schema gap. However, with only one parameter, the baseline is higher; the description implies a file path is needed but doesn't clarify format (e.g., absolute vs. relative path, supported extensions). This results in a minimal viable score due to the low parameter count.

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 'Open an existing Excel file' clearly states the action (open) and resource (Excel file), but it's somewhat vague about what 'open' means operationally. It distinguishes from siblings like 'excel_create_workbook' (creating new files) but doesn't specify if this loads the file into memory, makes it editable, or just reads it. The purpose is understandable but lacks specificity about the tool's operational behavior.

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 provides no guidance on when to use this tool versus alternatives. There's no mention of prerequisites (e.g., file must exist), when not to use it (e.g., for creating new files), or how it relates to siblings like 'excel_read_worksheet' or 'excel_merge_files'. Without annotations or context, the agent must infer usage from the name alone, which is insufficient for clear decision-making.

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