Update Properties

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

The annotations already indicate readOnlyHint=false, destructiveHint=true (modification), and idempotentHint=true. The description adds critical behavioral details: the return is a confirmation message (not the updated note), errors list includes 'not found', 'path traversal blocked', 'hidden path blocked', and 'concurrent write in progress' with recovery advice. It also warns that arrays are replaced entirely and that property type mismatches cause silent query failures. This goes well beyond the 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 well-structured with clear sections: operation semantics, example, when-to-use (with alternatives), error handling, and Obsidian syntax. It is informative but slightly long; some error details could be condensed. However, every sentence adds value, and the front-loading of the core operation is effective.

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 has 2 parameters (both required, no enums), no output schema, and annotations providing some but not exhaustive behavioral cues, the description covers all essential aspects: operation semantics, usage with examples, error conditions with handling advice, and Obsidian-specific formatting rules. No critical gaps remain for an agent to invoke this tool correctly.

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%, so the schema already documents both parameters. The description adds an example showing exact syntax for properties (including null deletion and arrays), lists Obsidian-specific conventions (use arrays for multi-value fields, quote wikilinks, keep types consistent), and notes that properties property uses shallow merge. This provides meaningful context beyond the schema's property descriptions.

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 tool updates a note's frontmatter properties via shallow merge, explaining the exact semantics (new keys added, matching keys overwritten, null deletes, unmentioned keys preserved). It also specifies that the body is never modified, which distinguishes it from sibling tools like vault_replace_in_note or vault_write_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 explicitly says when to use this tool (changing tags, status, type, or any property without reading/rewriting the full note body) and also specifies alternatives: pref er vault_write_note when creating a new note or replacing the body, and read current properties first with vault_read_note for arrays (since they are replaced entirely). This provides clear guidance on tool selection.

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