Obsidian MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions the UI interaction aspect and a plugin requirement, but doesn't describe what 'open' actually does (e.g., does it bring the file to foreground, open in new tab, trigger visual effects?), whether it requires specific permissions, or what happens on failure. For a UI-interaction tool with zero annotation coverage, this leaves significant behavioral gaps.

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, efficient sentence that states the core purpose and a key requirement. It's appropriately sized and front-loaded with the main action. However, it could be slightly more structured by separating the requirement into a second sentence for clarity.

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 moderate complexity (UI interaction with prerequisites), no annotations, and no output schema, the description is minimally adequate. It covers the what and a key requirement, but lacks details on behavioral outcomes, error handling, or UI-specific effects. For a tool that interacts with a UI, more context about what 'open' entails would be beneficial.

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 description coverage is 100%, with both parameters ('vault' and 'filepath') clearly documented in the schema. The description doesn't add any parameter-specific information beyond what the schema provides, such as format examples or constraints. With high schema coverage, the baseline score of 3 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 action ('Open a file') and the target resource ('in Obsidian UI'), which provides a specific verb+resource combination. However, it doesn't explicitly distinguish this tool from similar siblings like 'get_file' or 'get_active_file' in terms of UI vs. data retrieval functionality.

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 mentions a prerequisite ('requires REST API plugin'), which provides some context, but offers no guidance on when to use this tool versus alternatives like 'get_file' (which might retrieve file content without UI interaction) or 'open_graph' (which opens a different UI view). No explicit when/when-not or alternative recommendations are provided.

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