obsidian_frontmatter

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

With no annotations, the description carries the full burden of behavioral disclosure. It does reveal the dual read/update nature of the tool and clearly signals that update mode is a mutation. However, it does not disclose whether updates merge or replace existing frontmatter keys, whether frontmatter is created if absent, or what happens on error, leaving meaningful side-effect uncertainty.

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 a single concise sentence with no filler. The core action and resource 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 simple two-parameter tool, this is adequate but not complete. There is no output schema, yet the description does not state what a read operation returns, nor does it explain update merge/replace behavior or the case where a note has no frontmatter. An agent can call the tool correctly, but would have to assume several edge-case behaviors.

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 baseline is 3. The description adds mild semantic color with examples like tags, status, and date, but it does not clarify how the schema's string-only values map onto potentially structured frontmatter fields such as tags. The schema itself carries the real parameter documentation burden.

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 uses a specific verb pair ('Read or update') tied to a concrete resource ('YAML frontmatter of a note'), and even gives example fields. This clearly distinguishes it from generic siblings like obsidian_read and obsidian_write, which operate on full notes rather than frontmatter specifically.

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 makes the intended context clear: working with YAML frontmatter metadata such as tags, status, and date. It does not explicitly name alternatives or say when not to use this tool, but the specialization is strong enough that an agent can infer when to reach for it over the broader note-reading and note-writing siblings.

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