write-frontmatter-set

Call the obsidian-router set_frontmatter MCP tool with arguments parsed from $ARGUMENTS.

Arguments

Required:

• path — file path relative to vault root.
• key — frontmatter property name (e.g. status, tags, score).
• value — new value. Supports any of: string, number, boolean, null, array, object. Types are preserved end-to-end (a number stays a number in YAML, an array stays an array, etc.).

Optional:

• vault — omit for default.
• createIfMissing — create the key if absent. Default true.

Argument parsing from $ARGUMENTS

• <path> <key>=<value> — common shorthand (single key=value pair after the path)
• path=X key=Y value=Z — explicit
• --no-create → set createIfMissing=false

Type inference from $ARGUMENTS

• numeric literal (e.g. 3.14) → number
• true/false → boolean
• null → null
• starts with [ → JSON-parse as array
• starts with { → JSON-parse as object
• otherwise → string

On failure — remediate, NEVER fall back to filesystem writes

If the call fails, do NOT silently redo it with direct-filesystem tools (Read/Edit/Write on the vault's real path):

• Connection error (ECONNREFUSED, timeout) → vault closed; list_vaults, then ask the user to open it via the openUri link and wait.
• Validation / API error (HTTP 4xx) → fix the arguments — still through the router.

Rationale + message template: the default-vault-health-check convention (canonical source).

Output

After the set, confirm: <path>: <key> = <value>.

For setting multiple keys at once, prefer write-frontmatter-merge.