update_metadata

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

With no annotations, the description carries the full behavioral burden. It adds the key merge behavior ('preserving existing fields'), clarifies that metadata_json contains fields to update/add, and states that a success or error message is returned. This is meaningful behavioral context beyond the schema, though it does not mention permissions, reversibility, or what happens when the note does not exist.

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 compact and well-structured, with a clear one-line purpose followed by Args and Returns sections. Every sentence adds value and the key behavioral detail ('preserving existing fields') is front-loaded.

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?

For a simple two-parameter tool with an output schema, the description covers purpose, parameters, merge behavior, and return type. It is largely complete, but the lack of any guidance about when to choose this over related note-updating tools is a small gap given the large sibling list.

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 0%, so the description must compensate. It does: note_path is described as relative to vault root, and metadata_json is described as a JSON string containing fields to update/add. This adds real semantics beyond the raw schema, though an example or constraints on JSON structure would push it higher.

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 names a specific verb ('Update'), a specific resource ('frontmatter metadata in a note'), and a distinguishing behavior ('preserving existing fields'). This clearly separates it from broader note-editing siblings like append_to_note or replace_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 implies when to use the tool—when you need to modify or add frontmatter metadata—but it does not explicitly state when not to use it or mention alternatives. Usage context is inferable from the purpose, but no exclusions or sibling routing are provided.

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