update_frontmatter

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

With no annotations, the description carries the full burden. 'Merge' usefully communicates that the operation is additive/updating rather than wholesale replacement of the frontmatter. However, it does not disclose whether frontmatter is created if absent, how nested updates are handled, or what side effects or return values should be expected.

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?

A single short sentence with no filler. The verb ('Merge') and resource ('YAML frontmatter') are front-loaded, and every word earns its place.

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 mutation tool with no annotations, no output schema, and zero schema description coverage, the context is too thin. An agent must infer critical details about the updates object, path resolution, return values, and failure modes.

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 implies that updates is the payload of keys to merge and path identifies the note, but it never explicitly defines the path format, the requirement for updates to be an object of key-value pairs, or merge semantics for nested keys.

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 states a specific action—'Merge keys'—and a precise target: 'a note's YAML frontmatter.' This clearly separates it from content-focused siblings like append_to_note and patch_section, though it does not explicitly name alternatives, so it falls just short of a 5.

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?

There is no explicit guidance about when to use this tool versus alternatives such as create_note, patch_section, or append_to_note. The description implies its niche (frontmatter editing) but provides no exclusions or routing.

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