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

Annotations already indicate this is a non-readOnly, non-destructive, idempotent operation. The description adds valuable context beyond annotations: it specifies that parent directories are created automatically and clarifies the tool's behavior for both new and existing files (overwrites). This enhances understanding of the tool's operational traits without contradicting 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 front-loaded with the core action and key behavioral detail (automatic directory creation), followed by usage examples. Both sentences are necessary and efficient, with no redundant information, making it appropriately sized and well-structured for quick comprehension.

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 (write operation with two parameters), rich annotations, and no output schema, the description is mostly complete. It covers purpose, behavior, and usage context, but lacks details on error handling or response format. However, annotations provide safety cues, making it sufficient for effective use.

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 clear descriptions for both parameters (path and content). The description adds minimal semantic value beyond the schema—it implies the path is for file storage and content is markdown, but doesn't provide additional details like format constraints or examples. Baseline 3 is appropriate as the schema adequately covers 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 clearly states the verb ('write or overwrite') and resource ('a file in the Obsidian vault'), distinguishing it from sibling tools like vault_read, vault_list, and vault_search. It specifies the action includes automatic parent directory creation and mentions use cases (creating wiki pages, updating existing ones, saving markdown content), making the purpose explicit and differentiated.

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 clear context on when to use this tool ('to create new wiki pages, update existing ones, or save any markdown content'), but it does not explicitly state when not to use it or name alternatives. For example, it doesn't contrast with vault_frontmatter or other write-related tools, though the context is sufficient for basic guidance.

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