open_file

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

No annotations are provided, so the description must disclose behavior on its own. It only says 'open' in the interface, without explaining side effects (e.g., whether it focuses the window, changes the active file, or returns any response). There is no mention of safety or lack of mutation, leaving the operational behavior largely opaque.

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, clear sentence with no redundant words. It is concise and front-loaded, immediately stating the tool's purpose.

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 absence of annotations and output schema, the description is too sparse for full operational completeness. It does not explain what 'open in the Obsidian interface' means for programmatic use, whether it returns content, or how it relates to sibling tools like get_file. The context signals show a simple tool, but the description still leaves significant gaps.

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 covers 100% of parameters (filename and newLeaf) with descriptions. The tool description adds no additional parameter meaning, but the schema already does the heavy lifting. Baseline 3 is appropriate since the schema fully documents parameter semantics.

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 a file in the Obsidian interface' clearly states the action (open) and the resource (a file in Obsidian). It implies a UI operation, which distinguishes it from file-reading or writing tools like get_file and create_or_update_file, though it does not explicitly name alternatives.

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?

There is no guidance on when to use this tool versus alternatives. It does not mention that this is for interacting with the Obsidian UI rather than retrieving file contents, nor does it specify prerequisites like the vault being open. The description provides no context for appropriate use.

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