$ca-task — task-board writer

The one blessed way to mutate <project-root>/.codearbiter/open-tasks.md (resolves D-1). Hand-editing the board is no longer the only path; this command keeps every entry schema-conformant and every transition dated. The board LOGIC lives in the pure _taskboardlib transforms; this command runs the thin writer taskwrite.py from the selected installed package.

Before an authorized board mutation, read the installed helper card:

includes/helper-invocation.md relative to this loaded skill.

Set its loaded-resource input to the absolute path of this loaded command or skill, and select the literal relative helper hooks/taskwrite.py. Resolve and check that helper exactly once using the card, then run its interpreter-selection block for the current shell. Run from the intended project worktree so the writer targets that project's board. Do not switch to the plugin directory, use a root token from a hook environment in an ordinary tool call, or search source/cache copies.

Verbs

Always put -- before user text (a desc or title) so a value beginning with - is not parsed as a flag. Use the validated Python 3 interpreter selected by the card; never retry a refused helper under another interpreter. Keep every option before -- and pass user text as one literal argument.

• add — append a queued task. ID-less by default; pass --id <group>.<type> to mint a dotted ID now, --from <origin> for a harvest back-ref, --boundaries a,b for the security/trust boundaries it touches. The description must be nonblank and single-line; origin and boundary values must also stay on one line.
  • Invoke the resolved helper with add [--id group.type] [--from origin] [--boundaries a,b] -- <desc>.
• start — flip a task to in-progress and stamp the started date (so it can never be a dateless [~]). On an ID-less item, pass --as <group>.<type> to mint its dotted ID at pick-up. --date YYYY-MM-DD overrides today.
  • Invoke the resolved helper with start [--as group.type] [--date YYYY-MM-DD] -- <id|title>.
• done — flip an in-progress task to done and stamp the done date (--date overrides today). A queued task must be started first.
  • Invoke the resolved helper with done [--date YYYY-MM-DD] -- <id|title>.

The following are literal minimal add invocations after the installed helper and interpreter have been resolved. Bind the named text variable to the exact caller-supplied description; do not paste that text into the command syntax.

PowerShell add invocation

& $caPython -B $caHelper add -- $caDescription
if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }

POSIX add invocation

"$ca_python" -B "$ca_helper" add -- "$ca_description"

When add needs fields, bind each value separately and keep all options before --. Use the --from=<value> form if the origin begins with a hyphen. These examples preserve quotes, metacharacters, and non-ASCII description text as one argument; neither shell evaluates the variable's contents as a command.

PowerShell add with options

$caAddArgs = @('add', '--id', $caId, "--from=$caOrigin", '--boundaries', $caBoundaries, '--', $caDescription)
& $caPython -B $caHelper @caAddArgs
if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }

POSIX add with options

"$ca_python" -B "$ca_helper" add --id "$ca_id" "--from=$ca_origin" --boundaries "$ca_boundaries" -- "$ca_description"

For start and done, replace only the verb and its literal option array, keeping the same resolved helper and -- before the one title or ID argument.

A missing target, an already-matching state, an out-of-order transition, a malformed add field or --date, or an invalid GROUP.TYPE namespace is reported and writes nothing (exit 1). A queued done identifies the task as queued and tells the caller to start it first. Targeting by title is best-effort: prefer the dotted ID, and note that if two ID-less items share a title, start/done act on the first — give one an ID ($ca-task start --as <group>.<type> -- "<title>") to disambiguate.

When NOT to use

• Promoting workflow follow-ups in bulk → that is the harvest (includes/harvest.md), which calls this writer for you.
• Reading the board / counts → $ca-status (read-only).
• Archiving long-settled done items → $ca-standup owns the sweep (D-2, resolved 2026-07-31). It proposes dated done items strictly more than 14 calendar days old and requires a separate yes for each item before invoking the same installed taskwrite.py with archive <id>. This is the helper's archive verb, not a new public $ca-task archive mode. Undated done items are never proposed automatically; standup's explicit-request and --allow-undated rules apply. Declined items stay on the board.
• Filing a separate chore(board) PR just to flip a task state → task-board transitions ([x] done-flip, [~] start-flip, new [ ] add) ride the work commit via commit-gate, co-located atomically with the code that completes, starts, or spawns the task (ADR-0008). A lagging board-only PR is the anti-pattern this design eliminates.

Hard gate

• MUST write the board only through taskwrite.py (the pure transforms), never a free-hand Edit that can malform the schema.
• start MUST stamp a started date — never leave a dateless [~].
• done MUST target an in-progress task — a queued task must go through start first.
• MUST NOT delete a task to "complete" it — mark it done so the record survives.