Update note frontmatter

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

With no annotations, the description carries the full burden, and it does disclose the key behavioral facts: a merge (other keys are preserved) and null-based key removal. It says nothing about permissions, error handling when the note is missing, or how YAML types are coerced.

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?

Two tightly packed sentences; the core operation and its deletion semantic lead, and the use-case list follows. No wasted words.

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 two-parameter mutation tool with no output schema and no annotations, the description supplies the essentials: merge semantics, deletion mechanism, and intended use cases. Missing only peripheral behavioral notes (auth, 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 100%, so both parameters (ref, updates) are already documented in the schema; baseline 3 applies. The description adds only a hint that the keys are things like status/priority/due, which is marginal value over the schema's 'Keys to set; null deletes a key'.

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?

States a specific verb ('Merge keys into') and resource ('a note's YAML frontmatter'), plus the null-deletion semantic that defines the operation. It is distinguishable from siblings like replace_note_body or append_note by resource, though no sibling is named explicitly.

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?

'Use for status, priority, due, area, tags, aliases' gives concrete context for when this tool applies. There is no statement of when not to use it or which sibling to prefer for body edits, so it falls short of a full routing guideline.

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