obsidian_add_tag

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. It merely states the action without detailing whether duplicates are allowed, if existing tags are preserved, or what happens on error. This is insufficient for a mutation tool.

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 concise with a structured Args and Returns section. It avoids fluff but the Returns line is vague ('Success message or error'). Still, it is well-organized and efficient.

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?

With an output schema present (context signal), the description's vagueness on return values is somewhat mitigated. However, it lacks behavioral details like idempotency or error conditions, which are important for a simple mutation tool. It is minimally complete.

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 parameter descriptions add value beyond the schema, especially noting that the tag should be provided without the '#' prefix. Given zero schema description coverage, this compensates partially, though more detail on path format would help.

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 'Add a tag to a note.' This is a specific verb+resource combination that distinguishes it from sibling tools like obsidian_remove_tag or obsidian_rename_tag_in_note.

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 (e.g., when to use add_tag vs set_property). It does not mention prerequisites such as the note needing to exist, nor does it explain the context for its use.

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